seat: fix keyboard/pointer/touch resource destroy

We need to always unlink the resource, even if it's already inert.
seat_client_destroy_*() may be called multiple times on the same
resource.

Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3638

types/seat/wlr_seat_keyboard.c

@@ -473,11 +473,6 @@ void seat_client_create_inert_keyboard(struct wl_client *client,
 }
 
 void seat_client_destroy_keyboard(struct wl_resource *resource) {
-	struct wlr_seat_client *seat_client =
-		seat_client_from_keyboard_resource(resource);
-	if (seat_client == NULL) {
-		return;
-	}
 	wl_list_remove(wl_resource_get_link(resource));
 	wl_list_init(wl_resource_get_link(resource));
 	wl_resource_set_user_data(resource, NULL);

types/seat/wlr_seat_pointer.c

@@ -553,11 +553,6 @@ void seat_client_create_inert_pointer(struct wl_client *client,
 }
 
 void seat_client_destroy_pointer(struct wl_resource *resource) {
-	struct wlr_seat_client *seat_client =
-		wlr_seat_client_from_pointer_resource(resource);
-	if (seat_client == NULL) {
-		return;
-	}
 	wl_list_remove(wl_resource_get_link(resource));
 	wl_list_init(wl_resource_get_link(resource));
 	wl_resource_set_user_data(resource, NULL);

types/seat/wlr_seat_touch.c

@@ -454,11 +454,6 @@ void seat_client_create_inert_touch(struct wl_client *client, uint32_t version,
 }
 
 void seat_client_destroy_touch(struct wl_resource *resource) {
-	struct wlr_seat_client *seat_client =
-		seat_client_from_touch_resource(resource);
-	if (seat_client == NULL) {
-		return;
-	}
 	wl_list_remove(wl_resource_get_link(resource));
 	wl_list_init(wl_resource_get_link(resource));
 	wl_resource_set_user_data(resource, NULL);