net: bridge: don't cache ether dest pointer on input

[ Upstream commit 3d26eb8ad1e9b906433903ce05f775cf038e747f ]

We would cache ether dst pointer on input in br_handle_frame_finish but
after the neigh suppress code that could lead to a stale pointer since
both ipv4 and ipv6 suppress code do pskb_may_pull. This means we have to
always reload it after the suppress code so there's no point in having
it cached just retrieve it directly.

Fixes: 057658cb ("bridge: suppress arp pkts on BR_NEIGH_SUPPRESS ports")
Fixes: ed842fae ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>