uboot-imx

colibri_imx7_emmc: add Colibri iMX7D 1GB (eMMC) module support

This commit adds support for the Toradex Colibri iMX7D 1GB Computer
on Module. The module is very similar to the Colibri iMX7D 512MB
but uses eMMC instead of raw NAND. This patch introduces a new
board specific Kconfig symbol to select between the two flash
options.

Signed-off-by: Stefan Agner <stefan.agner@toradex.com>