ARM: pxa: moved pxa27x_keypad.h to platform pxa directory

mach-mmp utilizes pxa27x_keypad code so we need to move header to
platform pxa directory.

Signed-off-by: Mark F. Brown <mark.brown314@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

arch/arm/mach-pxa/tavorevb.c

@@ -25,7 +25,7 @@
 
 #include <mach/pxa930.h>
 #include <mach/pxafb.h>
-#include <mach/pxa27x_keypad.h>
+#include <plat/pxa27x_keypad.h>
 
 #include "devices.h"
 #include "generic.h"