scsi: storvsc: Enable multi-queue support

scsi: storvsc: Enable multi-queue support

BugLink: http://bugs.launchpad.net/bugs/1663687
Enable multi-q support. We will allocate the outgoing channel using
the following policy:

        1. We will make every effort to pick a channel that is in the
           same NUMA node that is initiating the I/O
        2. The mapping between the guest CPU and the outgoing channel
           is persistent.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(back ported from linux-next commit d86adf482b843b3a58a9ec3b7c1ccdbf7c705db1)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Conflicts:
	drivers/scsi/storvsc_drv.c