MAINTAINERS: remove rt2x00.serialmonkey.com list and web page

rt2x00.serialmonkey.com will be shutdown.

Since traffic on rt2x00 mailing list is very low, we can use only
linux-wireless list for any rt2x00 related topics.

Thanks for Luis Correia, Ivo van Doorn and Mark Wallis for maintaining
rt2x00 servers for years!

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

MAINTAINERS

@@ -8156,8 +8156,6 @@ P:	rt2x00 project
 M:	Stanislaw Gruszka <sgruszka@redhat.com>
 M:	Helmut Schaa <helmut.schaa@googlemail.com>
 L:	linux-wireless@vger.kernel.org
-L:	users@rt2x00.serialmonkey.com (moderated for non-subscribers)
-W:	http://rt2x00.serialmonkey.com/
 S:	Maintained
 F:	drivers/net/wireless/rt2x00/