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>
diff --git a/arch/arm/mach-pxa/littleton.c b/arch/arm/mach-pxa/littleton.c
index 83f3236..eb58506 100644
--- a/arch/arm/mach-pxa/littleton.c
+++ b/arch/arm/mach-pxa/littleton.c
@@ -43,7 +43,7 @@
 #include <mach/pxafb.h>
 #include <mach/mmc.h>
 #include <mach/pxa2xx_spi.h>
-#include <mach/pxa27x_keypad.h>
+#include <plat/pxa27x_keypad.h>
 #include <mach/littleton.h>
 #include <plat/i2c.h>
 #include <plat/pxa3xx_nand.h>