ARM: dts: Add twl keypad map for omap3 EVM

Looks like we're still missing the keypad map for EVM.
Let's add it since we have the binding now available
for the twl4030_keypad as otherwise we get the following
errors during the boot:

twl4030_keypad keypad.31: OF: linux,keymap property not defined
in /ocp/i2c@48070000/twl@48/keypad
twl4030_keypad keypad.31: Failed to build keymap
twl4030_keypad: probe of keypad.31 failed with error -2
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/omap3-evm-common.dtsi

@@ -2,6 +2,7 @@
  * Common support for omap3 EVM boards
  */
 
+#include <dt-bindings/input/input.h>
 #include "omap-gpmc-smsc911x.dtsi"
 
 / {
@@ -111,6 +112,26 @@ &twl_gpio {
 	ti,use-leds;
 };
 
+&twl_keypad {
+	linux,keymap = <
+			MATRIX_KEY(2, 2, KEY_1)
+			MATRIX_KEY(1, 1, KEY_2)
+			MATRIX_KEY(0, 0, KEY_3)
+			MATRIX_KEY(3, 2, KEY_4)
+			MATRIX_KEY(2, 1, KEY_5)
+			MATRIX_KEY(1, 0, KEY_6)
+			MATRIX_KEY(1, 3, KEY_7)
+			MATRIX_KEY(3, 1, KEY_8)
+			MATRIX_KEY(2, 0, KEY_9)
+			MATRIX_KEY(2, 3, KEY_KPASTERISK)
+			MATRIX_KEY(0, 2, KEY_0)
+			MATRIX_KEY(3, 0, KEY_KPDOT)
+			/* s4 not wired */
+			MATRIX_KEY(1, 2, KEY_BACKSPACE)
+			MATRIX_KEY(0, 1, KEY_ENTER)
+			>;
+};
+
 &usb_otg_hs {
 	interface-type = <0>;
 	usb-phy = <&usb2_phy>;