ixgbe: Fix handling of FDIR_HASH flag

ixgbe: Fix handling of FDIR_HASH flag

This change makes it so that we can use the atr_sample_rate to determine if
we are capable of supporting ATR. The advantage to this approach is that it
allows us to now determine the setting of the IXGBE_FLAG_FDIR_HASH_CAPABLE
based on the queueing scheme, instead of the queueing scheme being based on
the flag.

Using this approach there are essentially 5 conditions that must be checked
prior to trying to enable ATR:
1.  Is SR-IOV disabled?
2.  Are the number of TCs <= 1?
3.  Is RSS queueing limit greater than 1?
4.  Is atr_sample_rate set?
5.  Is Flow Director perfect filtering disabled?

If any of these conditions are enabled they should disable ATR filtering.
Note that in the case of conditions 1 through 4 being met we will set
things up for ATR queueing, however if test 5 fails we will still leave the
queues allocated for use by perfect filters.  The reason for this is to
allow for us to switch back and forth between ntuple and ATR without
needing to reallocate the descriptor rings.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>