storvsc: Set the SRB flags correctly when no data transfer is needed

[ Upstream commit dc45708c ]

Set the SRB flags correctly when there is no data transfer.  Without this
change some IHV drivers will fail valid commands such as TEST_UNIT_READY.

Cc: <stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>