net: fib_rules: Pass net to fib_nl2rule() instead of skb.

net: fib_rules: Pass net to fib_nl2rule() instead of skb.

skb is not used in fib_nl2rule() other than sock_net(skb->sk),
which is already available in callers, fib_nl_newrule() and
fib_nl_delrule().

Let's pass net directly to fib_nl2rule().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250207072502.87775-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>