board: toradex: add verdin imx8m plus support

This adds initial support for the Toradex Verdin iMX8M Plus Quad 4GB WB
IT V1.0B module. They are strapped to boot from eFuses which are factory
fused to properly boot from their on-module eMMC. U-Boot supports
booting from the on-module eMMC only, SDP support is disabled for now
due to missing i.MX 8M Plus USB support.

Functionality wise the following is known to be working:
- eMMC, 8-bit and 4-bit MMC/SD card slots
- Ethernet both on-module eQoS and FEC (requires PHY on carrier board)
- GPIOs
- I2C

Boot sequence is:
SPL ---> ATF (TF-A) ---> U-boot proper

ATF, U-boot proper and u-boot.dtb images are packed into a FIT image,
loaded by SPL.

Boot:
U-Boot SPL 2022.04-rc1-00164-g21a0312611-dirty (Feb 07 2022 - 11:34:04 +0100)
Quad die, dual rank failed, attempting dual die, single rank configuration.
Normal Boot
WDT:   Started watchdog@30280000 with servicing (60s timeout)
Trying to boot from BOOTROM
Find img info 0x&48025a00, size 872
Need continue download 1024
Download 779264, Total size 780424
NOTICE:  BL31: v2.2(release):rel_imx_5.4.70_2.3.2_rc1-5-g835a8f67b
NOTICE:  BL31: Built : 16:52:37, Aug 26 2021

U-Boot 2022.04-rc1-00164-g21a0312611-dirty (Feb 07 2022 - 11:34:04 +0100)

CPU:   Freescale i.MX8MP[8] rev1.1 at 1200 MHz
Reset cause: POR
DRAM:  8 GiB
Core:  78 devices, 18 uclasses, devicetree: separate
WDT:   Started watchdog@30280000 with servicing (60s timeout)
MMC:   FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... OK
In:    serial
Out:   serial
Err:   serial
Model: Toradex Verdin iMX8M Plus Quad 4GB Wi-Fi / BT IT V1.0B, Serial# 06817281
Carrier: Toradex Verdin Development Board V1.1A, Serial# 10807609
Setting variant to wifi
Net:   Hard-coding pdata->enetaddr
eth1: ethernet@30be0000, eth0: ethernet@30bf0000 [PRIME]
Hit any key to stop autoboot:  0
Verdin iMX8MP #

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/board/toradex/verdin-imx8mp/MAINTAINERS b/board/toradex/verdin-imx8mp/MAINTAINERS
new file mode 100644
index 0000000..5820546
--- /dev/null
+++ b/board/toradex/verdin-imx8mp/MAINTAINERS
@@ -0,0 +1,10 @@
+Verdin iMX8M Plus
+F:	arch/arm/dts/imx8mp-verdin.dts
+F:	arch/arm/dts/imx8mp-verdin-u-boot.dtsi
+F:	board/toradex/verdin-imx8mp/
+F:	configs/verdin-imx8mp_defconfig
+F:	doc/board/toradex/verdin-imx8mp.rst
+F:	include/configs/verdin-imx8mp.h
+M:	Marcel Ziswiler <marcel.ziswiler@toradex.com>
+S:	Maintained
+W:	https://www.toradex.com/computer-on-modules/verdin-arm-family/nxp-imx-8m-plus