ip_tunnels: allow VXLAN/GENEVE to inherit TOS/TTL from VLAN

ip_tunnels: allow VXLAN/GENEVE to inherit TOS/TTL from VLAN

The current code allows for VXLAN and GENEVE to inherit the TOS
respective the TTL when skb-protocol is ETH_P_IP or ETH_P_IPV6.
However when the payload is VLAN encapsulated, then this inheriting
does not work, because the visible skb-protocol is of type
ETH_P_8021Q or ETH_P_8021AD.

Instead of skb->protocol use skb_protocol().

Signed-off-by: Matthias May <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>