Use the named SINCE_VERSION defines for version checks

To make our code more clear.

src/compositor.c

@@ -3145,7 +3145,7 @@ bind_output(struct wl_client *client,
 				output->subpixel,
 				output->make, output->model,
 				output->transform);
-	if (version >= 2)
+	if (version >= WL_OUTPUT_SCALE_SINCE_VERSION)
 		wl_output_send_scale(resource,
 				     output->current_scale);
 
@@ -3157,7 +3157,7 @@ bind_output(struct wl_client *client,
 				    mode->refresh);
 	}
 
-	if (version >= 2)
+	if (version >= WL_OUTPUT_DONE_SINCE_VERSION)
 		wl_output_send_done(resource);
 }
 

src/input.c

@@ -1829,7 +1829,7 @@ bind_seat(struct wl_client *client, void *data, uint32_t version, uint32_t id)
 		caps |= WL_SEAT_CAPABILITY_TOUCH;
 
 	wl_seat_send_capabilities(resource, caps);
-	if (version >= 2)
+	if (version >= WL_SEAT_NAME_SINCE_VERSION)
 		wl_seat_send_name(resource, seat->seat_name);
 }