Add #includes needed to permit the removal of asm/system.h

asm/system.h is a cause of circular dependency problems because it contains
commonly used primitive stuff like barrier definitions and uncommonly used
stuff like switch_to() that might require MMU definitions.

asm/system.h has been disintegrated by this point on all arches into the
following common segments:

 (1) asm/barrier.h

     Moved memory barrier definitions here.

 (2) asm/cmpxchg.h

     Moved xchg() and cmpxchg() here.  #included in asm/atomic.h.

 (3) asm/bug.h

     Moved die() and similar here.

 (4) asm/exec.h

     Moved arch_align_stack() here.

 (5) asm/elf.h

     Moved AT_VECTOR_SIZE_ARCH here.

 (6) asm/switch_to.h

     Moved switch_to() here.

Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/include/linux/mtd/map.h b/include/linux/mtd/map.h
index 94e924e..ade5c99 100644
--- a/include/linux/mtd/map.h
+++ b/include/linux/mtd/map.h
@@ -31,6 +31,7 @@
 #include <asm/unaligned.h>
 #include <asm/system.h>
 #include <asm/io.h>
+#include <asm/barrier.h>
 
 #ifdef CONFIG_MTD_MAP_BANK_WIDTH_1
 #define map_bankwidth(map) 1