scsi: add option to override the command timeout

Some platforms might be very slow and command completion may take
much longer than default scsi command timeouts.
SCSI Read/Write command timeout can be changed by blk_queue_rq_timeout()
but there is no option to override timeout for rest of the scsi commands.
This change allows the LLD to override the default scsi command timeout
for all scsi commands (except read/write).

Change-Id: Ia36c1b1ca30f86844003d7187e84bec9ed8e22a9
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[cang@codeaurora.org: Resolved trivial merge conflicts]
Signed-off-by: Can Guo <cang@codeaurora.org>