locking/rwsem-rt: Remove might_sleep() in __up_read()

There's no chance of sleeping here, the reader is giving up the
lock and possibly waking up the writer who is waiting on it.

Reported-by: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/locking/rwsem-rt.c

@@ -198,7 +198,6 @@ void __up_read(struct rw_semaphore *sem)
 	if (!atomic_dec_and_test(&sem->readers))
 		return;
 
-	might_sleep();
 	raw_spin_lock_irq(&m->wait_lock);
 	/*
 	 * Wake the writer, i.e. the rtmutex owner. It might release the