net/vxlan: Fix kernel unaligned access in __vxlan_find_mac

net/vxlan: Fix kernel unaligned access in __vxlan_find_mac

Orabug: 24593619

Backport of upstream commit 7177a3b037c7 ("net/vxlan: Fix kernel
unaligned access in __vxlan_find_mac")

__vxlan_find_mac invokes ether_addr_equal on the eth_addr field,
which triggers unaligned access messages, so rearrange vxlan_fdb
to avoid this in the most non-intrusive way.

Reviewed-by: Jiri Pirko <jiri@resnulli.us>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit aa51c7b55e350240c2ed5a8a217688d5bfd13424)
Signed-off-by: Allen Pais <allen.pais@oracle.com>