intel-ethernet: rename i40evf to iavf

Rename the Intel Ethernet Adaptive Virtual Function driver
(i40evf) to a new name (iavf) that is more consistent with
the ongoing maintenance of the driver as the universal VF driver
for multiple product lines.

This first patch fixes up the directory names and the .ko name,
intentionally ignoring the function names inside the driver
for now.  Basically this is the simplest patch that gets
the rename done and will be followed by other patches that
rename the internal functions.

This patch also addresses a couple of string/name issues
and updates the Copyright year.

Also, made sure to add a MODULE_ALIAS to the old name.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>