atomic_t: Cast to volatile when accessing atomic variables

In preparation for removing volatile from the atomic_t definition, this
patch adds a volatile cast to all the atomic read functions.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/m68k/include/asm/atomic_mm.h b/arch/m68k/include/asm/atomic_mm.h
index d9d2ed6..6a223b3 100644
--- a/arch/m68k/include/asm/atomic_mm.h
+++ b/arch/m68k/include/asm/atomic_mm.h
@@ -15,7 +15,7 @@
 
 #define ATOMIC_INIT(i)	{ (i) }
 
-#define atomic_read(v)		((v)->counter)
+#define atomic_read(v)		(*(volatile int *)&(v)->counter)
 #define atomic_set(v, i)	(((v)->counter) = i)
 
 static inline void atomic_add(int i, atomic_t *v)