gui: fix return value of NotifyKey

Only the last action got its keys and ate all of them (om nom nom).
This fixes the power button action that activates the lock screen.

Change-Id: Ia724568b159090c2c14a282cf3927915b2dc70e7

gui/terminal.cpp

@@ -833,6 +833,8 @@ int GUITerminal::NotifyTouch(TOUCH_STATE state, int x, int y)
 
 int GUITerminal::NotifyKey(int key, bool down)
 {
+	if (!HasInputFocus)
+		return 1;
 	if (down)
 		if (engine->inputKey(key))
 			mUpdate = 1;