net/mlx5e: Allow TC csum offload if applied together with pedit action

When offloading header re-writes, the HW re-calculates the relevant L3/L4
checksums. Hence, when upper layers (as done by OVS) ask for TC checksum action
offload together with pedit offload, don't err. This command now works:

tc filter add dev ens1f0 protocol ip parent ffff: prio 20 flower skip_sw
	ip_proto tcp dst_port 9001
	action pedit ex munge tcp dport set 0x1234 pipe
        action csum tcp

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reported-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>