Revert "android: binder: Fix preemption and locking issues"

This reverts commit f48e2696.

No longer needed as of 4.9.38 as binder has been reformatted to use
fine-grained locking.

Change-Id: I7126d0e576b78a4c6a879ab849ba46e7f2a0b627
Signed-off-by: Kyle Yan <kyan@codeaurora.org>