[SCSI] mpt2sas: change queue depth with reason argument more appropriately

change_queue_depth callback API changed
The change_queue_depth callback changed where there is now an additional
parameter called reason, with SCSI_QDEPTH_DEFAULT, SCSI_QDEPTH_QFULL,
and SCSI_QDEPTH_RAMP_UP codes.

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