Revert "ipvlan: add L2 check for packets arriving via virtual devices"

This reverts commit 92ff4264.

Even though the check added is not that taxing, it's not really needed.
First of all this will be per packet cost and second thing is that the
eth_type_trans() already does this correctly. The excessive scrubbing
in IPvlan was changing the pkt-type skb metadata of the packet which
made it necessary to re-check the mac. The subsequent patch in this
series removes the faulty packet-scrub.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>