Set the expected default path to /boot/dtb/allwinner and
start analyzing if the DTB file is not found in this path.

The folder with the vendor's name is now part of the path,
not part of the file name. This greatly facilitates the analysis
of various possible options in a simple u-boot shell.

Inform the user about the actual file that will be uploaded
on the first iteration. Inform the user that it cannot be
downloaded only once if the first iteration was unsuccessful.

In the second iteration, we check the path that does not
contain the vendor folder. But this will also be done if
the real path contains the vendor's folder and the vendor's
name is contained in the DTB file name as
    fdtfile=allwinner/sun50i-*-bananapi-*.dtb.
However, overlays will not be available.
Remove "allwinner/" from all board configurations that
use the boot script mechanism so that the script works
correctly.

Signed-off-by: The-going <[email protected]>

Use the DTB name from the u-boot default for the third
iteration if the provided DTB name was not found. Also
delete the duplicate of the previous iteration.

Make the script work silently when testing path options
and report only the actual file being uploaded.
Delete the duplicate iteration.

After that, the script successfully loads the DTB file from
two possible paths and overlays. If the file does not exist,
then the default file will be uploaded.