locking/static_keys: Rework update logic

locking/static_keys: Rework update logic

Instead of spreading the branch_default logic all over the place,
concentrate it into the one jump_label_type() function.

This does mean we need to actually increment/decrement the enabled
count _before_ calling the update path, otherwise jump_label_type()
will not see the right state.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from 706249c222f68471b6f8e9e8e9b77665c404b226)

Orabug: 28607548

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>