[PATCH] Update Prism54 MAINTAINERS entry

prism54-private@prism54.org bounces with

    SMTP error from remote mailer after RCPT TO:<prism54-private@prism54.org>:
    host mx1.tuxfamily.net [212.85.158.8]: 550 unknown user

developers@islsm.org seems to be the new mailing list.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

MAINTAINERS

@@ -2646,7 +2646,7 @@ S:	Supported
 
 PRISM54 WIRELESS DRIVER
 P:	Prism54 Development Team
-M:	prism54-private@prism54.org
+M:	developers@islsm.org
 L:	netdev@vger.kernel.org
 W:	http://prism54.org
 S:	Maintained