ARM: dts: imx6ul-kontron: Add imx6ull-kontron-bl to Makefile

The imx6ull-kontron-bl.dtb wasn't build as part of the
CONFIG_SOC_IMX6UL option. Add it to the list.
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/Makefile

@@ -736,6 +736,7 @@ dtb-$(CONFIG_SOC_IMX6UL) += \
 	imx6ull-colibri-wifi-iris.dtb \
 	imx6ull-colibri-wifi-iris-v2.dtb \
 	imx6ull-jozacp.dtb \
+	imx6ull-kontron-bl.dtb \
 	imx6ull-myir-mys-6ulx-eval.dtb \
 	imx6ull-opos6uldev.dtb \
 	imx6ull-phytec-segin-ff-rdk-nand.dtb \