net: ipv6: Check that received src address is not mine

Drop received packet if the source address is the same as
the device address.

Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>
(cherry picked from commit 8d3d48e0575b59b19b559884ab4bce86ec5667a5)
1 file changed