locking, mips: Fix atomics

locking, mips: Fix atomics

The patch folding the atomic ops had two silly fails in the _return
primitives.

Fixes: ef31563e950c ("locking,arch,mips: Fold atomic_ops")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20140902202126.GA3190@worktop.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>