i40e: cleanup ATR auto_disable_flags use

Some locations that disable ATR accidentally used the "full" disable by
disabling the flag in the standard flags field. This incorrectly forces
ATR off permanently instead of temporarily disabling it. In addition,
some code locations accidentally set the ATR flag enabled when they only
meant to clear the auto_disable_flags. This results in ignoring the
user's ethtool private flag settings.

Additionally, when disabling ATR via ethtool, we did not perform a flush
of the FD table. This results in the previously assigned ATR rules still
functioning which was not expected.

Cleanup all these areas so that automatic disable uses only the
auto_disable_flag. Fix the flush code so that we can trigger a flush
even when we've disabled ATR and SB support, as otherwise the flush
doesn't work. Fix ethtool setting to actually request a flush. Fix
NETIF_F_NTUPLE flag to only clear the auto_disable setting and not
enable the full feature.

Change-ID: Ib2486111f8031bd16943e9308757b276305c03b5
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>