fix(PeriphDrivers): Fix -Wcast-align warning for MAX78000 & MAX78002 SYS Drivers

[Jake-Carter]

Pull Request Template

Description

This PR fixes the -Wcast-align errors for the MAX78000 & MAX78002 USN calculations. Our AES struct enforces 32-bit data alignment, so this solution uses an intermediate buffer and memcpy's out to the user's buffers.

- CC /home/jakecarter/repos/fork/msdk/Libraries/CMSIS/../PeriphDrivers/Source/SYS/sys_ai85.c
/home/jakecarter/repos/fork/msdk/Libraries/CMSIS/../PeriphDrivers/Source/SYS/sys_ai85.c: In function 'MXC_SYS_GetUSN':
/home/jakecarter/repos/fork/msdk/Libraries/CMSIS/../PeriphDrivers/Source/SYS/sys_ai85.c:120:29: warning: cast increases required alignment of target type [-Wcast-align]
  120 |         aes_req.inputData = (uint32_t *)usn;
      |                             ^
/home/jakecarter/repos/fork/msdk/Libraries/CMSIS/../PeriphDrivers/Source/SYS/sys_ai85.c:121:30: warning: cast increases required alignment of target type [-Wcast-align]
  121 |         aes_req.resultData = (uint32_t *)check_csum;
      |                              ^

Test Program

// project.mk
PROJ_CFLAGS += -Wcast-align -Werror

// main.c
#include "mxc_sys.h"

int main(void) {
    uint8_t usn[MXC_SYS_USN_LEN];
    uint8_t checksum[MXC_SYS_USN_CSUM_FIELD_LEN];

    int err = MXC_SYS_GetUSN(usn, checksum);
    if (err)
        printf("USN error: %i\n", err);

    printf("USN: 0x");
    for (int i = 0; i < MXC_SYS_USN_LEN; i++) {
        printf("%x", usn[i]);
    }
    printf("\n");
    printf("Checksum: 0x%x\n", checksum[0] | (checksum[1] << 8));

   return 0;
}

• MA78000 (PASS):

USN: 0xa184932241e4effdaee9bc
Checksum: 0xbce9

• MAX78002 (PASS):

USN: 0xa186889024015501ce32f7
Checksum: 0xf732

Checklist Before Requesting Review

• PR Title follows correct guidelines.
• Description of changes and all other relevant information.
• (Optional) Link any related GitHub issues using a keyword
• (Optional) Provide info on any relevant functional testing/validation. For API changes or significant features, this is not optional.

[Jacob-Scheiffler]

This check for a null pointer is redundant.

[Jake-Carter]

d4e5384

[Jacob-Scheiffler]

Are we gonna see this warning on other parts as well?

[Jake-Carter]

Are we gonna see this warning on other parts as well?

Not by default. We should eventually apply this to the other micros, but at a low priority