vxlan: Remove unnecessary comments for vxlan_rcv() and vxlan_err_lookup()

Remove the two unnecessary comments around vxlan_rcv() and
vxlan_err_lookup(), which indicate that the callers are from
net/ipv{4,6}/udp.c. These callers are trivial to find. Additionally, the
comment for vxlan_rcv() missed that the caller could also be from
net/ipv6/udp.c.

Suggested-by: Nikolay Aleksandrov <razor@blackwall.org>
Suggested-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Ted Chen <znscnchen@gmail.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250206140002.116178-1-znscnchen@gmail.com


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