arch: arm64: add WAIT_AT_RESET_VECTOR config

On platforms where reset vector catch is not possible
it is useful to have a compile-time option to spin
at the reset vector allowing a debugger to be attached
and then to manually resume execution.

Define a config option for arm64 to spin at the
reset vectdor so a debugger can be attached.

Signed-off-by: Eugene Cohen <quic_egmc@quicinc.com>