board: gateworks: venice: update board doc to show other emmc parts

Update the venice board documentation to show how to install to the
various eMMC hardware partitions available as the same binary firmware
can be placed in either user/boot0/boot1 without build-time config
changes. Note that the boot offsets differ depending on the SoC and the
eMMC hardware partition.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
3 files changed