raw: Fix mixed declarations error in raw_icmp_error().

The trailing semicolon causes a compiler error, so let's remove it.

net/ipv4/raw.c: In function ‘raw_icmp_error’:
net/ipv4/raw.c:266:2: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
  266 |  struct hlist_nulls_head *hlist;
      |  ^~~~~~

Fixes: ba44f818 ("raw: use more conventional iterators")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>