Merge branch 'xdp-vlan'

Jesper Dangaard Brouer says:

====================
While implementing PoC building blocks for eBPF code XDP+TC that can
manipulate VLANs headers, I discovered a bug in generic-XDP.

The fix should be backported to stable kernels.  Even-though
generic-XDP was introduced in v4.12, I think the bug is not exposed
until v4.14 in the mentined fixes commit.
====================

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>