MAINTAINERS: add board bindings list to OMAP2+ files

Add list of OMAP2+ boards to the corresponding section

CC: linux-omap@vger.kernel.org
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Message-ID: <20230515074512.66226-3-andreas@kemnade.info>
Signed-off-by: Tony Lindgren <tony@atomide.com>

MAINTAINERS

@@ -15505,6 +15505,7 @@ W:	http://www.muru.com/linux/omap/
 W:	http://linux.omap.com/
 Q:	http://patchwork.kernel.org/project/linux-omap/list/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git
+F:	Documentation/devicetree/bindings/arm/ti/omap.yaml
 F:	arch/arm/configs/omap2plus_defconfig
 F:	arch/arm/mach-omap2/
 F:	drivers/bus/ti-sysc.c