i2c: sam0: Add support for SAME54

[benpicco]

It shares the same peripheral with other sam0 parts while differing in the clock config.

split off from #14685

[zephyrbot]

All checks passed.

checkpatch (informational only, not a failure)

-:17: WARNING:PREFER_KERNEL_TYPES: Prefer kernel type 'u32_t' over 'uint32_t'
#17: FILE: drivers/i2c/i2c_sam0.c:28:
+	volatile uint32_t *mclk;

-:56: WARNING:LONG_LINE: line over 80 characters
#56: FILE: drivers/i2c/i2c_sam0.c:767:
+#define DT_ATMEL_SAM0_I2C_SERCOM_IRQ(n, m) DT_ATMEL_SAM0_I2C_SERCOM_ ## n ## _IRQ_ ## m

-:57: WARNING:LONG_LINE: line over 80 characters
#57: FILE: drivers/i2c/i2c_sam0.c:768:
+#define DT_ATMEL_SAM0_I2C_SERCOM_IRQ_PRIORITY(n, m) DT_ATMEL_SAM0_I2C_SERCOM_ ## n ## _IRQ_ ## m ## _PRIORITY

-:60: WARNING:SUSPECT_CODE_INDENT: suspect code indent for conditional statements (8, 8)
#60: FILE: drivers/i2c/i2c_sam0.c:771:
+	do {								\
+	IRQ_CONNECT(DT_ATMEL_SAM0_I2C_SERCOM_IRQ(n, m),			\

-:87: WARNING:LONG_LINE: line over 80 characters
#87: FILE: drivers/i2c/i2c_sam0.c:798:
+		.regs = (SercomI2cm *)DT_ATMEL_SAM0_I2C_SERCOM_##n##_BASE_ADDRESS, \

- total: 0 errors, 5 warnings, 122 lines checked

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NOTE: Ignored message types: AVOID_EXTERNS BRACES CONFIG_EXPERIMENTAL CONST_STRUCT DATE_TIME FILE_PATH_CHANGES MINMAX NETWORKING_BLOCK_COMMENT_STYLE PRINTK_WITHOUT_KERN_LEVEL SPLIT_STRING VOLATILE

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      them to the maintainers.

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