ARC: atomic_cmpxchg/atomic_xchg: implement relaxed variants

And move them out of cmpxchg.h to canonical atomic.h

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

arch/arc/include/asm/atomic.h

@@ -22,6 +22,33 @@
 #include <asm/atomic-spinlock.h>
 #endif
 
+#define arch_atomic_cmpxchg(v, o, n)					\
+({									\
+	arch_cmpxchg(&((v)->counter), (o), (n));			\
+})
+
+#ifdef arch_cmpxchg_relaxed
+#define arch_atomic_cmpxchg_relaxed(v, o, n)				\
+({									\
+	arch_cmpxchg_relaxed(&((v)->counter), (o), (n));		\
+})
+#endif
+
+#define arch_atomic_xchg(v, n)						\
+({									\
+	arch_xchg(&((v)->counter), (n));				\
+})
+
+#ifdef arch_xchg_relaxed
+#define arch_atomic_xchg_relaxed(v, n)					\
+({									\
+	arch_xchg_relaxed(&((v)->counter), (n));			\
+})
+#endif
+
+/*
+ * 64-bit atomics
+ */
 #ifdef CONFIG_GENERIC_ATOMIC64
 #include <asm-generic/atomic64.h>
 #else