board: gateworks: venice: add imx8mm-gw7902 support

The GW7902 is based on the i.MX 8M Mini / Nano SoC featuring:
- LPDDR4 DRAM
- eMMC FLASH
- Gateworks System Controller
- LTE CAT M1 modem
- USB 2.0 HUB
- M.2 Socket with USB2.0, PCIe, and dual-SIM
- IMX8M FEC
- PCIe based GbE
- RS232/RS485/RS422 serial transceiver
- GPS
- CAN bus
- WiFi / Bluetooth
- MIPI header (DSI/CSI/GPIO/PWM/I2S)
- PMIC

Do the following to add support for it:
- add dts
- add PMIC config

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
diff --git a/arch/arm/dts/imx8mm-venice-gw7902-u-boot.dtsi b/arch/arm/dts/imx8mm-venice-gw7902-u-boot.dtsi
new file mode 100644
index 0000000..361ddaa
--- /dev/null
+++ b/arch/arm/dts/imx8mm-venice-gw7902-u-boot.dtsi
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2021 Gateworks Corporation
+ */
+
+#include "imx8mm-u-boot.dtsi"
+
+&gpio1 {
+	u-boot,dm-spl;
+};
+
+&gpio2 {
+	u-boot,dm-spl;
+};
+
+&gpio3 {
+	u-boot,dm-spl;
+};
+
+&gpio4 {
+	u-boot,dm-spl;
+};
+
+&gpio5 {
+	u-boot,dm-spl;
+};
+
+&uart2 {
+	u-boot,dm-spl;
+};
+
+&pinctrl_uart2 {
+	u-boot,dm-spl;
+};
+
+&usdhc3 {
+	u-boot,dm-spl;
+};
+
+&pinctrl_usdhc3 {
+	u-boot,dm-spl;
+};
+
+&i2c1 {
+	u-boot,dm-spl;
+};
+
+&pinctrl_i2c1 {
+	u-boot,dm-spl;
+};
+
+&i2c2 {
+	u-boot,dm-spl;
+};
+
+&pinctrl_i2c2 {
+	u-boot,dm-spl;
+};
+
+&fec1 {
+	phy-reset-gpios = <&gpio1 10 GPIO_ACTIVE_LOW>;
+	phy-reset-duration = <1>;
+	phy-reset-post-delay = <1>;
+};
+
+&pinctrl_fec1 {
+	u-boot,dm-spl;
+};
+
+&{/soc@0/bus@30800000/i2c@30a20000/pmic@4b} {
+	u-boot,dm-spl;
+};
+
+&{/soc@0/bus@30800000/i2c@30a20000/pmic@4b/regulators} {
+	u-boot,dm-spl;
+};
+
+&pinctrl_pmic {
+	u-boot,dm-spl;
+};