imx6: tbs2910: fix dtb build error

Fix broken build:
Device Tree Source is not correctly specified.
Please define 'CONFIG_DEFAULT_DEVICE_TREE'
or build with 'DEVICE_TREE=<device_tree>' argument

Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 5a8d855..0fb6419 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -503,6 +503,9 @@
 	imx6q-display5.dtb \
 	imx6q-logicpd.dtb
 
+dtb-$(CONFIG_TARGET_TBS2910) += \
+	imx6q-tbs2910.dtb
+
 dtb-$(CONFIG_MX6QDL) += \
 	imx6dl-icore.dtb \
 	imx6dl-icore-mipi.dtb \