i40e: Use correct shift for VLAN priority

When using port VLAN, for VFs, and setting priority bits, the device
was sending out incorrect priority bits, and also setting the CFI
bit incorrectly.

To fix this, changed shift and mask bit definition for this function, to
use the correct ones.

Signed-off-by: Richard Rodriguez <richard.rodriguez@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>