Input: pxa27x_keypad add choice to set direct_key_mask

Direct keys usage may not start from KP_DKIN0, add a msk option
to configure the specifics for platforms that can skip some keys.

Signed-off-by: Chao Xie <chao.xie@marvell.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>

arch/arm/plat-pxa/include/plat/pxa27x_keypad.h

@@ -46,6 +46,8 @@ struct pxa27x_keypad_platform_data {
 	unsigned int	direct_key_map[MAX_DIRECT_KEY_NUM];
 	/* the key output may be low active */
 	int		direct_key_low_active;
+	/* give board a chance to choose the start direct key */
+	unsigned int	direct_key_mask;
 
 	/* rotary encoders 0 */
 	int		enable_rotary0;