mtip32xx: Increase timeout for standby command

Increased timeout for standby command to work with larger capacity drives

Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>