[SCSI] mptfusion: block device when target is being removed by FW

Add support to set the sdev state to SDEV_BLOCK during device removal
to stop IOs comming to the deleting driver immediately.

Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>