iavf: Enable support for up to 16 queues

Previous devices could only allocate 4 MSI-X vectors per VF so there was a
limitation of 4 queues. 800-series hardware can allocate more than 4 MSI-X
vectors, so expand the limitation on the number of queues that the driver
can support to account for these capabilities.

Fix ethtool channel operations to accommodate this change and adjust the
reporting of max number of queues to what is given to us by the PF. Since
we're not requesting queues above this value, just trigger reset to
activate the queues, which we already own.

Finally, fix a test condition that would display an incorrect error
message.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>