Enable HP_WATCHDOG for aarch64
HP watchdog is now supported on some HP aarch64 platforms, so enable it.
Also delete redhat/configs/pending-ark/generic/CONFIG_HP_WATCHDOG which was automatically added when ARM64 was added to HP_WATCHDOG supported arches. This had the unintended side effect of turning off HP_WATCHDOG for x86.
Signed-off-by: Mark Salter msalter@redhat.com