qede: Use NETIF_F_GRO_HW.

Advertise NETIF_F_GRO_HW and set edev->gro_disable according to the
feature flag.  Add qede_fix_features() to drop NETIF_F_GRO_HW if
XDP is running or MTU does not support GRO_HW or GRO is not set.
qede_change_mtu() also checks and disables GRO_HW if MTU is not
supported.

Cc: Ariel Elior <Ariel.Elior@cavium.com>
Cc: everest-linux-l2@cavium.com
Acked-by: Manish Chopra <manish.chopra@cavium.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Acked-by: Manish Chopra <manish.chopra@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>