This prevents gcc from incorrectly trying to validate array bounds.
```
tmk_core/common/chibios/bootloader.c: error: '__builtin_memcpy' offset [0, 21] is out of the bounds [0, 0] [-Werror=array-bounds]
107 | __builtin_memcpy((void *) VBAT, (const void *)sys_reset_to_loader_magic, sizeof(sys_reset_to_loader_magic));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c16Fixes#12925
