i.MX6: engicam: Include dts files under MAINTAINERS

dts files related to i.MX6 engicam boards are maintined
under board, so include them under board/engicam/*/MAINTAINERS

Cc: Stefano Babic <sbabic@denx.de>
Cc: Matteo Lisi <matteo.lisi@engicam.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

board/engicam/geam6ul/MAINTAINERS

@@ -5,3 +5,4 @@ F:	board/engicam/geam6ul
 F:	include/configs/imx6ul_geam.h
 F:	configs/imx6ul_geam_mmc_defconfig
 F:	configs/imx6ul_geam_nand_defconfig
+F:	arch/arm/dts/imx6ul-geam-kit.dts

board/engicam/icorem6/MAINTAINERS

@@ -7,3 +7,6 @@ F:	configs/imx6q_icore_mmc_defconfig
 F:	configs/imx6q_icore_nand_defconfig
 F:	configs/imx6dl_icore_mmc_defconfig
 F:	configs/imx6dl_icore_nand_defconfig
+F:	arch/arm/dts/imx6qdl-icore.dtsi
+F:	arch/arm/dts/imx6q-icore.dts
+F:	arch/arm/dts/imx6dl-icore.dts

board/engicam/icorem6_rqs/MAINTAINERS

@@ -5,3 +5,6 @@ F:	board/engicam/icorem6_rqs
 F:	include/configs/imx6qdl_icore_rqs.h
 F:	configs/imx6q_icore_rqs_mmc_defconfig
 F:	configs/imx6dl_icore_rqs_mmc_defconfig
+F:	arch/arm/dts/imx6qdl-icore-rqs.dtsi
+F:	arch/arm/dts/imx6q-icore-rqs.dts
+F:	arch/arm/dts/imx6dl-icore-rqs.dts