MAINTAINERS: update GPIO OMAP driver entry

I've been maintaining this driver by fixing all issues
found while migrating OMAP2+ towards Device Tree based
booting and keeping it up-to-date by using the latest
infraestructure that is provided by the GPIO subsystem.

It would be nice if people know that I care about this
driver and put me in copy when sending patches for it.
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

MAINTAINERS

@@ -6404,6 +6404,7 @@ F:	drivers/usb/*/*omap*
 F:	arch/arm/*omap*/usb*
 
 OMAP GPIO DRIVER
+M:	Javier Martinez Canillas <javier@dowhile0.org>
 M:	Santosh Shilimkar <santosh.shilimkar@ti.com>
 M:	Kevin Hilman <khilman@deeprootsystems.com>
 L:	linux-omap@vger.kernel.org