i40e: Implement configfs for NPAR BW configuration

Add configfs controls to get, set and commit NPAR BW configurations.

We export three controls:
	min_bw - Can take a value from 0 to 100 inclusive
	max_bw - Can take a value from 1 to 100 inclusive
	commit - A write-only control that accepts only a value of 1 and will
		cause the BW settings to be permanently committed to NVM so
		that they are persistent across power cycles and system
		resets

The BW values are relative and are expressed as percentages.  For more
information on the interpretation of the BW settings see the Dell
specifications for NPAR.

Also update the copyright year.

Change-ID: Id7496ca65630b5037e32ba6a5a748fbc1632881b
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Tested-By: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>