cxgb4: fix wrong ethtool n-tuple rule lookup

The TID returned during successful filter creation is relative to
the region in which the filter is created. Using it directly always
returns Hi Prio/Normal filter region's entry for the first couple of
entries, even though the rule is actually inserted in Hash region.
Fix by analyzing in which region the filter has been inserted and
save the absolute TID to be used for lookup later.

Fixes: db43b30c

 ("cxgb4: add ethtool n-tuple filter deletion")
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>