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>