MAINTAINERS: add Neal to TCP maintainers

Neal Cardwell has been indispensable in TCP reviews
and investigations, especially protocol-related.
Neal is also the author of packetdrill.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250129191332.2526140-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

MAINTAINERS

@@ -16525,6 +16525,7 @@ F:	tools/testing/selftests/net/mptcp/
 
 NETWORKING [TCP]
 M:	Eric Dumazet <edumazet@google.com>
+M:	Neal Cardwell <ncardwell@google.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
 F:	Documentation/networking/net_cachelines/tcp_sock.rst