MAINTAINERS: Remove link to oss.renesas.com which is closed

There doesn't seem much value in keeping this link listed
in the MAINTAINERS file any more.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

MAINTAINERS

@@ -1517,7 +1517,6 @@ ARM/SHMOBILE ARM ARCHITECTURE
 M:	Simon Horman <horms@verge.net.au>
 M:	Magnus Damm <magnus.damm@gmail.com>
 L:	linux-sh@vger.kernel.org
-W:	http://oss.renesas.com
 Q:	http://patchwork.kernel.org/project/linux-sh/list/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas.git next
 S:	Supported