add prebuilt u-boot for odroid-c1

[chewitt]

This PR is a hack/workaround for the current lack of support for 32-bit (Meson8) boards in upstream u-boot. It adds the prebuilt HK u-boot.bin file for the Odroid C1 board to the repo, allowing distro image experiments for C1 to use the same buildsystem workflows as other/newer Amlogic boards; e.g. in LE we create an upstream u-boot as the buildsystem has multiple assumptions around using it, but during the signing stage of creating a bootable .img we substitute the 2011.03 prebuilt needed to boot a C1 board.

[moonlinux]

what is the version of the u-boot used and are these some external patches on top of u-boot-c1 2011.03

[chewitt]

what is the version of the u-boot used

I have fuzzy recollection of downloading the u-boot.bin from the HK wiki, but I can't find any references to a prebuilt bin there now so I probably built it from source; in which case I used https://github.com/hardkernel/u-boot/commits/odroidc-v2011.03 which didn't receive any changes since June 2017. I'm highly confident I wouldn't have used any other source, as I honestly wouldn't know where else to look for C1 u-boot sources.

[moonlinux]

ok, no problem. Please let me know how to use this u-boot.bin