MIPS: locking/atomic: Fix atomic{_64,}_sub_if_positive

This looks like a typo and that caused atomic64 test failed.
Signed-off-by: Rui Wang <wangrui@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/include/asm/atomic.h

@@ -206,7 +206,7 @@ ATOMIC_OPS(atomic64, xor, s64, ^=, xor, lld, scd)
  * The function returns the old value of @v minus @i.
  */
 #define ATOMIC_SIP_OP(pfx, type, op, ll, sc)				\
-static __inline__ int arch_##pfx##_sub_if_positive(type i, pfx##_t * v)	\
+static __inline__ type arch_##pfx##_sub_if_positive(type i, pfx##_t * v)	\
 {									\
 	type temp, result;						\
 									\