[MTD] Don't include linux/mtd/map.h from linux/mtd/physmap.h

Replace the inclusion of linux/mtd/map.h with a forward-declaration
of struct map_info. This allows linux/mtd/physmap.h to be included by
e.g. board code even if the MTD subsystem is disabled.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

include/linux/mtd/physmap.h

@@ -18,9 +18,10 @@
 #define __LINUX_MTD_PHYSMAP__
 
 #include <linux/mtd/mtd.h>
-#include <linux/mtd/map.h>
 #include <linux/mtd/partitions.h>
 
+struct map_info;
+
 struct physmap_flash_data {
 	unsigned int		width;
 	void			(*set_vpp)(struct map_info *, int);