This adds a mapping for device trees which differ between vendor and mainline kernel and will therefore allow updates to new releases.
The old ones will be replaced by the new, or at least most appropriate (in case of RK3328 box devices), devicetrees in mainline kernel.
Besides a warning will be shown now if the device tree that the installation uses does not exist in the update tarball.
MiQi and Tinker devices have been merged to RK3288 device at some point after LE9.2 release.
This allows updating for them as well through mapping to the new RK3288 device.
While at that also drop the pointless check for kernel versions.
All required bootloader files are already copied by the u-boot package
(using the corresponding bootloader/install script) to the system's
/usr/share/bootloader directory. The dtb files are copied by the linux
package to the same spot.
Use that single source for the release tarballs instead of various
build directories.
