xtensa: change CONFIG_ATOMIC_OPERATIONS_ARCH to imply

Xtensa cores are highly configurable so each SoC may not have
the needed instructions for the hardware assisted atomic
operations. So instead of selecting the arch-specific atomic
operations kconfig, do a "imply" instead. So SoC or board
configs can disable this.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
1 file changed