mtip32xx: fix for crash when the device surprise removed during rebuild

When rebuild is in progress, disk->queue is yet to be created. Surprise
removing the device will call remove()-> del_gendisk(). del_gendisk()
expect disk->queue be not NULL. Fix is to call put_disk() when disk_queue
is NULL.
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/mtip32xx/mtip32xx.c

@@ -3888,7 +3888,12 @@ static int mtip_block_remove(struct driver_data *dd)
 	 * Delete our gendisk structure. This also removes the device
 	 * from /dev
 	 */
-	del_gendisk(dd->disk);
+	if (dd->disk) {
+		if (dd->disk->queue)
+			del_gendisk(dd->disk);
+		else
+			put_disk(dd->disk);
+	}
 
 	spin_lock(&rssd_index_lock);
 	ida_remove(&rssd_index_ida, dd->index);
@@ -3922,7 +3927,13 @@ static int mtip_block_shutdown(struct driver_data *dd)
 		"Shutting down %s ...\n", dd->disk->disk_name);
 
 	/* Delete our gendisk structure, and cleanup the blk queue. */
-	del_gendisk(dd->disk);
+	if (dd->disk) {
+		if (dd->disk->queue)
+			del_gendisk(dd->disk);
+		else
+			put_disk(dd->disk);
+	}
+
 
 	spin_lock(&rssd_index_lock);
 	ida_remove(&rssd_index_ida, dd->index);