i40e: set pf_id based on device and function numbers

pf_id needs to be encoded for cards with ARI enabled, which
allows for larger function numbers than 8.

Commit-Id: I23fa7df9dabf3878cc08c9b2151729c8539f5f17
Signed-off-by: Christopher Pau <christopher.pau@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>