MAINTAINERS: update GPIO maintainers entry

Add Alexandre Courbot as co-maintainer of the GPIO subsystem.
Provide a pointer to the GPIO GIT tree. Update the documentation
file path. Move around to put people and git tree on top.
Acked-by: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

MAINTAINERS

@@ -3765,9 +3765,11 @@ F:	include/uapi/linux/gigaset_dev.h
 
 GPIO SUBSYSTEM
 M:	Linus Walleij <linus.walleij@linaro.org>
-S:	Maintained
+M:	Alexandre Courbot <gnurou@gmail.com>
 L:	linux-gpio@vger.kernel.org
-F:	Documentation/gpio.txt
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git
+S:	Maintained
+F:	Documentation/gpio/
 F:	drivers/gpio/
 F:	include/linux/gpio*
 F:	include/asm-generic/gpio.h