Add skb drop reasons to IPv6 UDP receive path

Enumerate the skb drop reasons in the receive path for IPv6 UDP packets.

Signed-off-by: Donald Hunter <donald.hunter@redhat.com>
Link: https://lore.kernel.org/r/20220926120350.14928-1-donald.hunter@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>