ipmi: Add the git repository to the MAINTAINERS file

Advertise where the IPMI git repository is stored.
Signed-off-by: Corey Minyard <cminyard@mvista.com>

MAINTAINERS

@@ -10074,6 +10074,7 @@ M:	Corey Minyard <minyard@acm.org>
 L:	openipmi-developer@lists.sourceforge.net (moderated for non-subscribers)
 S:	Supported
 W:	http://openipmi.sourceforge.net/
+T:	git https://github.com/cminyard/linux-ipmi.git for-next
 F:	Documentation/driver-api/ipmi.rst
 F:	Documentation/devicetree/bindings/ipmi/
 F:	drivers/char/ipmi/