mtip32xx: Fix for rmmod crash when drive is in FTL rebuild
When FTL rebuild is in progress, alloc_disk() initializes the disk
but device node will be created by add_disk() only after successful
completion of FTL rebuild. So, skip deletion of device node in
removal path when FTL rebuild is in progress.
Signed-off-by: Selvan Mani <smani@micron.com> Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>