suspend: only join the hwbinder threadpool when HIDL is registered

When the HIDL service fails to register (typically when it's deprecated)
we have no reason to join the libhwbinder threadpool.
In that case, join the libbinder threadpool instead.

Test: launch_cvd
Bug: 331677082
Change-Id: I7a2882997571b7782d825ffca958a571aecee902
1 file changed