locking, sparc64: Fix atomics

The patch folding the atomic ops had a silly fail in the _return primitives.

Fixes: 4f3316c2b5fe ("locking,arch,sparc: 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: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/20140902094016.GD31157@worktop.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/sparc/lib/atomic_64.S

@@ -37,7 +37,7 @@ ENTRY(atomic_##op##_return) /* %o0 = increment, %o1 = atomic_ptr */	\
 	cas	[%o1], %g1, %g7;					\
 	cmp	%g1, %g7;						\
 	bne,pn	%icc, BACKOFF_LABEL(2f, 1b);				\
-	 add	%g1, %o0, %g1;						\
+	 op	%g1, %o0, %g1;						\
 	retl;								\
 	 sra	%g1, 0, %o0;						\
 2:	BACKOFF_SPIN(%o2, %o3, 1b);					\
@@ -76,7 +76,7 @@ ENTRY(atomic64_##op##_return) /* %o0 = increment, %o1 = atomic_ptr */	\
 	bne,pn	%xcc, BACKOFF_LABEL(2f, 1b);				\
 	 nop;								\
 	retl;								\
-	 add	%g1, %o0, %o0;						\
+	 op	%g1, %o0, %o0;						\
 2:	BACKOFF_SPIN(%o2, %o3, 1b);					\
 ENDPROC(atomic64_##op##_return);