sparc: asm/atomic.h on 32bit should include asm/system.h for xchg

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/include/asm/atomic_32.h

@@ -15,6 +15,8 @@
 
 #ifdef __KERNEL__
 
+#include <asm/system.h>
+
 #define ATOMIC_INIT(i)  { (i) }
 
 extern int __atomic_add_return(int, atomic_t *);