ANDROID: binder: Switch binder_deferred_lock to a spinlock.

Avoid delays in binder transactions due to preemption of
binder_deferred_func() with binder_deferred_lock held.

Bug: 66914906
Test: boots; binder tests pass; trace analysis in bug
Change-Id: I1a89ba15b27e43552890292f135a5e2d969231e2
Signed-off-by: Corey Tabaka <eieio@google.com>