Update HardwareSerial.h with 9-bit definitions

I added all the combinations of 9-bit serial.
9N1, 9N2, 9E1, 9E2, 9O1, 9O2, 9M1, 9M2, 9S1, 9S2
This allows newer processors like the RA4M1 to use its built-in 9-bit support. 9Bit is widely used on many industrial and embedded machines, and having a true 9-bit UART brings a high value add to these boards.

Author: vashadow

api/HardwareSerial.h

@@ -54,38 +54,47 @@ namespace arduino {
 #define SERIAL_6N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_6)
 #define SERIAL_7N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_7)
 #define SERIAL_8N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_8)
+#define SERIAL_9N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_9)
 #define SERIAL_5E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_5)
 #define SERIAL_6E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_6)
 #define SERIAL_7E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_7)
 #define SERIAL_8E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_8)
+#define SERIAL_9E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_9)
 #define SERIAL_5E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_5)
 #define SERIAL_6E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_6)
 #define SERIAL_7E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_7)
 #define SERIAL_8E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_8)
+#define SERIAL_9E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_9)
 #define SERIAL_5O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_5)
 #define SERIAL_6O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_6)
 #define SERIAL_7O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_7)
 #define SERIAL_8O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_8)
+#define SERIAL_9O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_9)
 #define SERIAL_5O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_5)
 #define SERIAL_6O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_6)
 #define SERIAL_7O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_7)
 #define SERIAL_8O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_8)
+#define SERIAL_9O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_9)
 #define SERIAL_5M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_5)
 #define SERIAL_6M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_6)
 #define SERIAL_7M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_7)
 #define SERIAL_8M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_8)
+#define SERIAL_9M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_9)
 #define SERIAL_5M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_5)
 #define SERIAL_6M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_6)
 #define SERIAL_7M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_7)
 #define SERIAL_8M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_8)
+#define SERIAL_9M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_9)
 #define SERIAL_5S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_5)
 #define SERIAL_6S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_6)
 #define SERIAL_7S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_7)
 #define SERIAL_8S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_8)
+#define SERIAL_9S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_9)
 #define SERIAL_5S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_5)
 #define SERIAL_6S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_6)
 #define SERIAL_7S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_7)
 #define SERIAL_8S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_8)
+#define SERIAL_9S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_9)
 
 class HardwareSerial : public Stream
 {