Improve Gamepad fallbacks for text entry.

Change-Id: Ia8b05730a9b41b93006e678aba2d182748e56083
diff --git a/data/keyboards/Generic.kcm b/data/keyboards/Generic.kcm
index 01d22ee..1ef74ba 100644
--- a/data/keyboards/Generic.kcm
+++ b/data/keyboards/Generic.kcm
@@ -492,11 +492,11 @@
 }
 
 key BUTTON_X {
-    base:                               fallback DPAD_CENTER
+    base:                               fallback DEL
 }
 
 key BUTTON_Y {
-    base:                               fallback BACK
+    base:                               fallback SPACE
 }
 
 key BUTTON_Z {