Disintegrate asm/system.h for Microblaze

Disintegrate asm/system.h for Microblaze.  Not compiled.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: microblaze-uclinux@itee.uq.edu.au
diff --git a/arch/microblaze/include/asm/atomic.h b/arch/microblaze/include/asm/atomic.h
index 615f539..472d8bf 100644
--- a/arch/microblaze/include/asm/atomic.h
+++ b/arch/microblaze/include/asm/atomic.h
@@ -1,6 +1,7 @@
 #ifndef _ASM_MICROBLAZE_ATOMIC_H
 #define _ASM_MICROBLAZE_ATOMIC_H
 
+#include <asm/cmpxchg.h>
 #include <asm-generic/atomic.h>
 #include <asm-generic/atomic64.h>