twister build issue with arm64

[galak]

Getting the following warning (treated as error):

From:

tests/misc/test_build/buildsystem.debug.build
tests/subsys/jwt/libraries.encoding.jwt

on:

qemu_cortex_a53_smp
nxp_ls1046ardb_smp

/workdir/zephyr/arch/arm64/core/smp.c: In function 'arch_start_cpu':
/workdir/zephyr/arch/arm64/core/smp.c:98:3: error: 'cpu_mpid' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   98 |   printk("Failed to boot secondary CPU core %d (MPID:%#llx)\n",
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   99 |          cpu_num, cpu_mpid);
      |          ~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors