[msm7630_surf]: Add key mapping to boot into recovery mode.

Add R+ key to boot into recovery mode for msm7630_surf target.
diff --git a/target/msm7630_surf/keypad.c b/target/msm7630_surf/keypad.c
index 516eab6..36a6e42 100644
--- a/target/msm7630_surf/keypad.c
+++ b/target/msm7630_surf/keypad.c
@@ -45,6 +45,7 @@
 
 static unsigned int qwerty_keymap[] = {
     [KEYMAP_INDEX(4, 2)] = KEY_BACK,          /* -L on SURF & FFA */
+    [KEYMAP_INDEX(3, 4)] = KEY_HOME,          /* +R on SURF & FFA */
     [KEYMAP_INDEX(1, 4)] = KEY_CLEAR,         /* '-' of left side switch on FLUID */
 };