power: supply: ab8500: Add MAINTAINERS entry

I am maintaining these drivers so add patterns to MAINTAINERS
for them.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

MAINTAINERS

@@ -260,6 +260,11 @@ W:	http://www.adaptec.com/
 F:	Documentation/scsi/aacraid.rst
 F:	drivers/scsi/aacraid/
 
+AB8500 BATTERY AND CHARGER DRIVERS
+M:	Linus Walleij <linus.walleij@linaro.org>
+F:	Documentation/devicetree/bindings/power/supply/*ab8500*
+F:	drivers/power/supply/*ab8500*
+
 ABI/API
 L:	linux-api@vger.kernel.org
 F:	include/linux/syscalls.h