udp_tunnel: Pass struct sock to udp_tunnel_{push,drop}_rx_port().

udp_tunnel: Pass struct sock to udp_tunnel_{push,drop}_rx_port().

None of the udp_tunnel users need struct socket in their
fast paths; it is only used for tunnel setup / teardown.

Even udp_tunnel_{push,drop}_rx_port() do not need struct socket.

Let's change udp_tunnel_{push,drop}_rx_port() to take struct
sock instead of struct socket.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260502031401.3557229-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>