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/configs/imx8mm_venice_defconfig b/configs/imx8mm_venice_defconfig
index e10f1b2..3da3fad 100644
--- a/configs/imx8mm_venice_defconfig
+++ b/configs/imx8mm_venice_defconfig
@@ -58,7 +58,7 @@
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_OF_CONTROL=y
 CONFIG_SPL_OF_CONTROL=y
-CONFIG_OF_LIST="imx8mm-venice-gw71xx-0x imx8mm-venice-gw72xx-0x imx8mm-venice-gw73xx-0x imx8mm-venice-gw7901"
+CONFIG_OF_LIST="imx8mm-venice-gw71xx-0x imx8mm-venice-gw72xx-0x imx8mm-venice-gw73xx-0x imx8mm-venice-gw7901 imx8mm-venice-gw7902"
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y