sh: Fix sh4a llsc-based cmpxchg()

This fixes up a typo in the ll/sc based cmpxchg code which apparently
wasn't getting a lot of testing due to the swapped old/new pair. With
that fixed up, the ll/sc code also starts using it and provides its own
atomic_add_unless().

Signed-off-by: Aoi Shinkai <shinkoi2005@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h
index 6327ffb..978b58e 100644
--- a/arch/sh/include/asm/atomic.h
+++ b/arch/sh/include/asm/atomic.h
@@ -45,7 +45,7 @@
 #define atomic_inc(v) atomic_add(1,(v))
 #define atomic_dec(v) atomic_sub(1,(v))
 
-#ifndef CONFIG_GUSA_RB
+#if !defined(CONFIG_GUSA_RB) && !defined(CONFIG_CPU_SH4A)
 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
 {
 	int ret;
@@ -73,7 +73,7 @@
 
 	return ret != u;
 }
-#endif
+#endif /* !CONFIG_GUSA_RB && !CONFIG_CPU_SH4A */
 
 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)