i40e: clean up comment style

Lots of trivial changes to remove double spaces in function headers,
unnecessary periods in short comments, and adjust the English usage here
and there.

No actual code was harmed in the making of this patch.

Change-ID: I6e756c500756945e81a61ffb10221753eb7923ea
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Kevin Scott <kevin.c.scott@intel.com>
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>