board: gateworks: venice: add imx8mm-gw7904 support

The GW7904 is based on the i.MX 8M Mini SoC featuring:
 - LPDDR4 DRAM
 - eMMC FLASH
 - microSD connector with UHS support
 - LIS2DE12 3-axis accelerometer
 - Gateworks System Controller
 - IMX8M FEC
 - 2x RS232 off-board connectors
 - PMIC
 - 10x bi-color LED's
 - 1x miniPCIe socket with PCIe and USB2.0
 - 802.3at Class 4 PoE
 - 10-30VDC input via barrel-jack

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 1da5041..30e69b9 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -957,6 +957,7 @@
 	imx8mm-venice-gw7901.dtb \
 	imx8mm-venice-gw7902.dtb \
 	imx8mm-venice-gw7903.dtb \
+	imx8mm-venice-gw7904.dtb \
 	imx8mm-verdin-wifi-dev.dtb \
 	phycore-imx8mm.dtb \
 	imx8mn-bsh-smm-s2.dtb \