uclogic: Disable pen usage for Huion keyboard interfaces

Disable pen usage inputs for Huion interfaces reporting on-the-frame
buttons. We don't want to change those, as they mostly work, but we want
to avoid creation of a mute pen interface, confusing to users.

Author: spbnick

hid-uclogic-params.c

@@ -705,7 +705,8 @@ static int uclogic_params_huion_init(struct uclogic_params *params,
 
 	/* If it's a custom keyboard interface */
 	if (bInterfaceNumber == 1) {
-		/* Keep everything intact */
+		/* Keep everything intact, but mark pen usage invalid */
+		p.pen.usage_invalid = true;
 		goto output;
 	/* Else, if it's not a pen interface */
 	} else if (bInterfaceNumber != 0) {