i40e/i40evf: force inline transmit functions

Inlining these functions gives us about 15% more 64 byte packets per
second when using pktgen. 13.3 million to 15 million with a single
queue.

Also fix the function names in i40evf to i40evf not i40e while we are
touching the function header.

Change-ID: I3294ae9b085cf438672b6db5f9af122490ead9d0
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>