CIrrDeviceLinux: fix dumb key fallback behaviour

Turns out giving the application KEY_UNKNOWN + the correct char
to work with is better than returning nonsense EKEY_CODEs.

Author: sfan5

source/Irrlicht/CIrrDeviceLinux.cpp

@@ -783,23 +783,18 @@ EKEY_CODE CIrrDeviceLinux::getKeyCode(XEvent &event)
 	}
 	if (keyCode == 0)
 	{
-		// Any value is better than none, that allows at least using the keys.
-		// Worst case is that some keys will be identical, still better than _all_
-		// unknown keys being identical.
+		keyCode = KEY_UNKNOWN;
 		if ( !mp.X11Key )
 		{
-			keyCode = (EKEY_CODE)event.xkey.keycode;
-			os::Printer::log("No such X11Key, using event keycode", core::stringc(event.xkey.keycode).c_str(), ELL_INFORMATION);
+			os::Printer::log("No such X11Key, event keycode", core::stringc(event.xkey.keycode).c_str(), ELL_INFORMATION);
 		}
 		else if (idx == -1)
 		{
-			keyCode = (EKEY_CODE)mp.X11Key;
-			os::Printer::log("EKEY_CODE not found, using orig. X11 keycode", core::stringc(mp.X11Key).c_str(), ELL_INFORMATION);
+			os::Printer::log("EKEY_CODE not found, X11 keycode", core::stringc(mp.X11Key).c_str(), ELL_INFORMATION);
 		}
 		else
 		{
-			keyCode = (EKEY_CODE)mp.X11Key;
-			os::Printer::log("EKEY_CODE is 0, using orig. X11 keycode", core::stringc(mp.X11Key).c_str(), ELL_INFORMATION);
+			os::Printer::log("EKEY_CODE is 0, X11 keycode", core::stringc(mp.X11Key).c_str(), ELL_INFORMATION);
 		}
  	}
 	return keyCode;