ARM: dts: imx: add Boundary Devices Nitrogen6_SoloX board

Based on i.MX6 SoloX with 1GB of RAM.

https://boundarydevices.com/product/nit6_solox-imx6/

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
index f54c518..eaf82b9 100644
--- a/arch/arm/boot/dts/Makefile
+++ b/arch/arm/boot/dts/Makefile
@@ -377,6 +377,7 @@
 	imx6sl-evk.dtb \
 	imx6sl-warp.dtb
 dtb-$(CONFIG_SOC_IMX6SX) += \
+	imx6sx-nitrogen6sx.dtb \
 	imx6sx-sabreauto.dtb \
 	imx6sx-sdb-reva.dtb \
 	imx6sx-sdb.dtb