* u-boot-install-sunxi64:
- Detect target based on running device-tree.
- Prefer BL31 from arm-trusted-firmware over atf-allwinner.
- Error out when mkimage is not found and Recommend u-boot-tools
(Closes: #913879). Thanks to Nicolas Schier.
* [arm64] u-boot-sunxi: Update Recommends to use arm-trusted-firmware
instead of atf-allwinner.
* [arm64] u-boot-amlogic: Add Recommends on arm-trusted-firmware.
* Update upstream signing key.