scsi: storvsc: use tagged SRB requests if supported by the device

scsi: storvsc: use tagged SRB requests if supported by the device

BugLink: http://bugs.launchpad.net/bugs/1663687
Properly set SRB flags when hosting device supports tagged queuing.
This patch improves the performance on Fiber Channel disks.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from linux-next commit 3cd6d3d9b1abab8dcdf0800224ce26daac24eea2)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>