net: stmmac: xgmac: Fix AV Feature detection

Fix incorrect precedence of operators. For reference: AV implies AV
Feature but RAV implies only RX side AV Feature. As we want full AV
features we need to check RAV.

Fixes: c2b69474

 ("net: stmmac: xgmac: Correct RAVSEL field interpretation")
Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>