locking/rwsem: Use task->state helpers

Call __set_task_state() instead of assigning the new state
directly. These interfaces also aid CONFIG_DEBUG_ATOMIC_SLEEP
environments, keeping track of who last changed the state.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422257769-14083-2-git-send-email-dave@stgolabs.net


Signed-off-by: Ingo Molnar <mingo@kernel.org>