ANDROID: binder: fix pending prio state for early exit

When calling binder_do_set_priority() with the same policy and priority
values as the current task, we exit early since there is nothing to do.
However, the BINDER_PRIO_PENDING state might be set and in this case we
fail to update it. A subsequent call to binder_transaction_priority()
will then read an incorrect state and save the wrong priority. Fix this
by setting thread->prio_state to BINDER_PRIO_SET on our way out.

Bug: 199309216
Fixes: cac827f2 ("ANDROID: binder: fix race in priority restore")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Change-Id: I21e906cf4b2ebee908af41fe101ecd458ae1991c
(cherry picked from commit 72193be6)