Update TDA998x maintainer entry

Update my TDA998x HDMI encoder MAINTAINERS entry to include the
dt-bindings header, and a keyword pattern to catch patches containing
the DT compatible.  Also change the status to "maintained" rather than
"supported".
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -10213,11 +10213,13 @@ F:	sound/soc/codecs/sgtl5000*
 
 NXP TDA998X DRM DRIVER
 M:	Russell King <linux@armlinux.org.uk>
-S:	Supported
+S:	Maintained
 T:	git git://git.armlinux.org.uk/~rmk/linux-arm.git drm-tda998x-devel
 T:	git git://git.armlinux.org.uk/~rmk/linux-arm.git drm-tda998x-fixes
 F:	drivers/gpu/drm/i2c/tda998x_drv.c
 F:	include/drm/i2c/tda998x.h
+F:	include/dt-bindings/display/tda998x.h
+K:	"nxp,tda998x"
 
 NXP TFA9879 DRIVER
 M:	Peter Rosin <peda@axentia.se>