MAINTAINERS: add git url for fpga

Add git url for fpga stuff.
Signed-off-by: Alan Tull <atull@opensource.altera.com>

MAINTAINERS

@@ -4958,6 +4958,7 @@ M:	Alan Tull <atull@opensource.altera.com>
 R:	Moritz Fischer <moritz.fischer@ettus.com>
 L:	linux-fpga@vger.kernel.org
 S:	Maintained
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/atull/linux-fpga.git
 F:	drivers/fpga/
 F:	include/linux/fpga/fpga-mgr.h
 W:	http://www.rocketboards.org