i40e: remove hw_disabled_flags in favor of using separate flag bits

The hw_disabled_flags field was added as a way of signifying that
a feature was automatically or temporarily disabled. However, we
actually only use this for FDir features. Replace its use with new
_AUTO_DISABLED flags instead. This is more readable, because you aren't
setting an *_ENABLED flag to *disable* the feature.

Additionally, clean up a few areas where we used these bits. First, we
don't really need to set the auto-disable flag for ATR if we're fully
disabling the feature via ethtool.

Second, we should always clear the auto-disable bits in case they somehow
got set when the feature was disabled. However, avoid displaying
a message that we've re-enabled the feature.

Third, we shouldn't be re-enabling ATR in the SB ntuple add flow,
because it might have been disabled due to space constraints. Instead,
we should just wait for the fdir_check_and_reenable to be called by the
watchdog.

Overall, this change allows us to simplify some code by removing an
extra field we didn't need, and the result should make it more clear as
to what we're actually doing with these flags.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>