bpf: Fix bpf_skc_lookup comment wrt. return type

The function no longer returns 'unsigned long' as of commit edbf8c01
("bpf: add skc_lookup_tcp helper").
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220617152121.29617-1-tklauser@distanz.ch

net/core/filter.c

@@ -6463,8 +6463,6 @@ static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple,
 
 /* bpf_skc_lookup performs the core lookup for different types of sockets,
  * taking a reference on the socket if it doesn't have the flag SOCK_RCU_FREE.
- * Returns the socket as an 'unsigned long' to simplify the casting in the
- * callers to satisfy BPF_CALL declarations.
  */
 static struct sock *
 __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,