preempt: Move preempt_enable_no_resched() to the RT block

preempt_enable_no_resched() should point to preempt_enable() on
PREEMPT_RT so nobody is playing any preempt tricks and enables
preemption without checking for the need-resched flag.

This was misplaced in v3.14.0-rt1 und remained unnoticed until now.

Point preempt_enable_no_resched() and preempt_enable() on RT.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>