Add Xilinx SystemACE entry to maintainers

I'm the author of the SystemACE driver
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

MAINTAINERS

@@ -4176,6 +4176,13 @@ W:	http://oss.sgi.com/projects/xfs
 T:	git git://oss.sgi.com:8090/xfs/xfs-2.6.git
 S:	Supported
 
+XILINX SYSTEMACE DRIVER
+P:	Grant Likely
+M:	grant.likely@secretlab.ca
+W:	http://www.secretlab.ca/
+L:	linux-kernel@vger.kernel.org
+S:	Maintained
+
 XILINX UARTLITE SERIAL DRIVER
 P:	Peter Korsgaard
 M:	jacmet@sunsite.dk