net/iavf: support requesting additional queues from PF

net/iavf: support requesting additional queues from PF

Add a new virtchnl function to request additional queues from PF.
Current default queue pairs number when creating a VF is 16. In order to
support up to 256 queue pairs per VF, enable this request queues
function.

When requesting queues succeeds, PF will return an event message. If it
is handled by interrupt first, the request queues command cannot receive
the correct PF response and will wait until timeout. Therefore, disable
interrupt before requesting queues in order to handle the event message
asynchronously.

Signed-off-by: Ting Xu <ting.xu@intel.com>
Acked-by: Beilei Xing <beilei.xing@intel.com>