seco-mx6 - edehog adaptations
This is a cleaner version of !142 (closed)
Changes:
- Changed mmc order to match linux.
- Changed to take env from emmc user partition with Edgehog offset - 0xc0000.
- Copied Edgehog env headers and seco_config cmd from u-boot-seco-imx.
- Performed initial update of seco-mx6 machine for the Edgehog env.
- Added workaround for overlay load cmd to board code.
About the last change - I may be missing something or this functionality either does not work or disabled in Edgehog u-boot out of the box.