The pumpkin board is made by Gossamer Engineering and is using
a MediaTek SoC. The board currently comes in two available version:
MT8516 SoC and MT8167 SoC.
The board provides the following IOs: eMMC, NAND, SD card, USB type-A,
Ethernet, Wi-Fi, Bluetooth, Audio (jack out, 2 PDM port, 1 analog in),
serial over USB, and an expansion header.
Additionally there is a HDMI port, DSI port, and camera port only
on the MT8167 version of the board.
The board can be powered by battery and/or via a USB Type-C port and
is using a PMIC MT6392.
The eMMC and NAND are sharing pins and cannot be used together.
This commit is adding the basic boot support for the Pumpkin MT8516
board on the eMMC.