compositor: Remove compositor->seat

Get rid of this quick-and-dirty assumption.

src/compositor-android.c

@@ -340,7 +340,6 @@ android_seat_create(struct android_compositor *compositor)
 	weston_seat_init(&seat->base, &compositor->base);
 	seat->base.led_update = android_led_update;
 	wl_list_init(&seat->devices_list);
-	compositor->base.seat = &seat->base;
 
 	android_seat_scan_devices(seat, "/dev/input");
 

src/compositor-drm.c

@@ -2037,8 +2037,6 @@ evdev_input_create(struct weston_compositor *c, struct udev *udev,
 	}
 
 	evdev_add_devices(udev, &seat->base);
-
-	c->seat = &seat->base;
 }
 
 static void

src/compositor.h

@@ -290,9 +290,6 @@ struct weston_compositor {
 	struct wl_event_loop *input_loop;
 	struct wl_event_source *input_loop_source;
 
-	/* There can be more than one, but not right now... */
-	struct weston_seat *seat;
-
 	struct weston_layer fade_layer;
 	struct weston_layer cursor_layer;