fb: mmp: include linux/platform_device.h

Commit 16559ae48c ("kgdb: remove #include <linux/serial_8250.h> from
kgdb.h") changes the kgdb.h file so that drivers including it do not
implicitly include linux/platform_device.h.  The mmp framebuffer driver
is new, so Greg did not have a chance to fix it up when introducing his
change.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Zhou Zhu <zzhu3@marvell.com>
Cc: Lisa Du <cldu@marvell.com>
Cc: Guoqing Li <ligq@marvell.com>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/mmp/fb/mmpfb.c

@@ -21,6 +21,7 @@
  */
 #include <linux/module.h>
 #include <linux/dma-mapping.h>
+#include <linux/platform_device.h>
 #include "mmpfb.h"
 
 static int var_to_pixfmt(struct fb_var_screeninfo *var)