include: arch: arm: Fix arch_curr_cpu() for Cortex-M

[gromero]

Currently, the arch_curr_cpu() implementation always uses the TPIDRURO register, even on Cortex-M CPUs where such a register is not available, causing a CPU fault.

For instance, on Cortex-M board b_u585i_iot02a, if this patch is applied to sample/hello_world:

(compiled with: $ west build -p always -b b_u585i_iot02a samples/hello_world/ -t flash)

 #include <stdio.h>
 
 int main(void)
 {
        printf("Hello World! %s\n", CONFIG_BOARD);
+       printf("arch_proc_id = %d\n", arch_proc_id());
        return 0;
 }

Call to arch_proc_id() will generate an illegal instruction due to the use of TPIDRURO mv instr:

Program received signal SIGINT, Interrupt.
arch_system_halt (reason=33) at /home/gromero/zephyrproject/zephyr/kernel/fatal.c:32
32		for (;;) {
(gdb) bt
#0  arch_system_halt (reason=33) at /home/gromero/zephyrproject/zephyr/kernel/fatal.c:32
#1  0x08002e00 in k_sys_fatal_error_handler (reason=<optimized out>, esf=esf@entry=0x20000ac0 <z_interrupt_stacks+1984>) at /home/gromero/zephyrproject/zephyr/kernel/fatal.c:46
#2  0x080017be in z_fatal_error (reason=<optimized out>, esf=esf@entry=0x20000ac0 <z_interrupt_stacks+1984>) at /home/gromero/zephyrproject/zephyr/kernel/fatal.c:122
#3  0x0800278e in z_arm_fatal_error (reason=<optimized out>, esf=esf@entry=0x20000ac0 <z_interrupt_stacks+1984>) at /home/gromero/zephyrproject/zephyr/arch/arm/core/fatal.c:73
#4  0x08000596 in z_arm_fault (msp=<optimized out>, psp=<optimized out>, exc_return=<optimized out>, callee_regs=<optimized out>) at /home/gromero/zephyrproject/zephyr/arch/arm/core/cortex_m/fault.c:1157
#5  0x08000654 in z_arm_usage_fault () at /home/gromero/zephyrproject/zephyr/arch/arm/core/cortex_m/fault_s.S:102
#6  <signal handler called>
#7  read_tpidruro () at /home/gromero/zephyrproject/zephyr/include/zephyr/arch/arm/cortex_a_r/lib_helpers.h:75
#8  arch_curr_cpu () at /home/gromero/zephyrproject/zephyr/include/zephyr/arch/arm/arch_inlines.h:17
#9  arch_proc_id () at /home/gromero/zephyrproject/zephyr/include/zephyr/arch/arm/arch_inlines.h:26
#10 main () at /home/gromero/zephyrproject/zephyr/samples/hello_world/src/main.c:13
(gdb) frame 7
#7  read_tpidruro () at /home/gromero/zephyrproject/zephyr/include/zephyr/arch/arm/cortex_a_r/lib_helpers.h:75
75	MAKE_REG_HELPER(tpidruro,    0, 13, 0, 3);
(gdb) disas
Dump of assembler code for function main:
   0x08000234 <+0>:	push	{r3, lr}
   0x08000236 <+2>:	ldr	r1, [pc, #28]	; (0x8000254 <main+32>)
   0x08000238 <+4>:	ldr	r0, [pc, #28]	; (0x8000258 <main+36>)
   0x0800023a <+6>:	bl	0x80020dc <printf>
=> 0x0800023e <+10>:			; <UNDEFINED> instruction: 0xee1d3f70
   0x08000242 <+14>:	bic.w	r3, r3, #3
   0x08000246 <+18>:	ldrb	r1, [r3, #16]
   0x08000248 <+20>:	ldr	r0, [pc, #16]	; (0x800025c <main+40>)
   0x0800024a <+22>:	bl	0x80020dc <printf>
   0x0800024e <+26>:	movs	r0, #0
   0x08000250 <+28>:	pop	{r3, pc}
   0x08000252 <+30>:	nop
   0x08000254 <+32>:	subs	r0, #2
   0x08000256 <+34>:	lsrs	r0, r0, #32
   0x08000258 <+36>:	subs	r0, #17
   0x0800025a <+38>:	lsrs	r0, r0, #32
   0x0800025c <+40>:	subs	r0, #34	; 0x22
   0x0800025e <+42>:	lsrs	r0, r0, #32
End of assembler dump.
(gdb)

This commit fixes it by reverting to the use of generic kernel struct to obtain the current cpu instead of using the TPIDRURO register on Cortex-M CPUs.

[gromero]

CC @SgrrZhf @erwango