tcp: Update stale comment for MD5 in tcp_parse_options().

Since commit 9ea88a15 ("tcp: md5: check md5 signature without socket
lock"), the MD5 option is checked in tcp_v[46]_rcv().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230803224552.69398-3-kuniyu@amazon.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv4/tcp_input.c

@@ -4126,9 +4126,8 @@ void tcp_parse_options(const struct net *net,
 				break;
 #ifdef CONFIG_TCP_MD5SIG
 			case TCPOPT_MD5SIG:
-				/*
-				 * The MD5 Hash has already been
-				 * checked (see tcp_v{4,6}_do_rcv()).
+				/* The MD5 Hash has already been
+				 * checked (see tcp_v{4,6}_rcv()).
 				 */
 				break;
 #endif