MAINTAINERS: update the official rdma git repo

Linus prefers kernel.org repos to github repos for security.
Signed-off-by: Doug Ledford <dledford@redhat.com>

MAINTAINERS

@@ -5048,7 +5048,7 @@ M:	Hal Rosenstock <hal.rosenstock@gmail.com>
 L:	linux-rdma@vger.kernel.org
 W:	http://www.openfabrics.org/
 Q:	http://patchwork.kernel.org/project/linux-rdma/list/
-T:	git git://github.com/dledford/linux.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma.git
 S:	Supported
 F:	Documentation/infiniband/
 F:	drivers/infiniband/