[SCSI] mptfusion: Use DID_TRANSPORT_DISRUPTED instead of DID_BUS_BUSY

Changed the return value for Nexus Loss IOs to be DID_TRANSPORT_DISRUPTED.
What this will allow is the multi-path driver to delay the fail over
process. They would like the path to keep up as long as the nexus loss
Loginfo is return from firmware. With DID_BUS_BUSY the path fails over
immediately.

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