i40e: rename auto_disable_flags to hw_disabled_flags

A previous commit introduced a field that tracks the features
that are disabled due to HW resource limitations as opposed
to the featured disabled by the user. This patch changes the
name of the field to make it more readable since it might get
confusing when looking at code containing both the flags
field and the auto_disable_features field together.

Change-ID: Idcc9888659698f6fe3ccff17c8c3f09b5026f708
Signed-off-by: Harshitha Ramamurthy <harshitha.ramamurthy@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>