Revert "ANDROID: binder: fix sleeping from invalid function caused by RT inheritance"

This reverts commit aefd2d63.

This patch introduced a race condition reported by Pete Zhang
<pete.zhang@nxp.com> where a thread already selected to handle a
transaction could be selected again by a different client. The signature
was triggering of the WARN_ON() in binder_enqueue_thread_work_ilocked():

static void
binder_enqueue_thread_work_ilocked(...)
{
	WARN_ON(!list_empty(&thread->waiting_thread_node));
	...
}

which indicates that a thread is unexpectedly enqueued
as a waiting thread when it has been selected and work is
being assigned to it.

There was a 2nd issue introduced by the same patch that could,
at least in theory, cause async transactions to hang.

Bug: 151861772
Change-Id: I0c2bdb4c4a0d57caae1551bcbb4c31a8e09e024b
Signed-off-by: Todd Kjos <tkjos@google.com>