samples: enlarge the stack size to run a sample successfully

CMSIS limits the stack size, but for qemu_x86_64, qemu_xtensa, qemu_leon3
and the boards sunch as up_squared, ehl_crb, acrn_ehl_crb need more
stack size to run this successfully, or the stack overflow will happened.
So we enlarge the stack size to 1024 for this sample case.

For other boards the original 512 is enough.

Signed-off-by: Enjia Mai <enjia.mai@intel.com>