MAINTAINERS: add maintainer entry for TDA998x driver

Add a maintainers entry for the TDA998x driver.  Rob Clark has handed
this driver over to me to look after.

Acked-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

MAINTAINERS

@@ -6171,6 +6171,12 @@ S:	Supported
 F:	drivers/block/nvme*
 F:	include/linux/nvme.h
 
+NXP TDA998X DRM DRIVER
+M:	Russell King <rmk+kernel@arm.linux.org.uk>
+S:	Supported
+F:	drivers/gpu/drm/i2c/tda998x_drv.c
+F:	include/drm/i2c/tda998x.h
+
 OMAP SUPPORT
 M:	Tony Lindgren <tony@atomide.com>
 L:	linux-omap@vger.kernel.org