Both boot artifacts now use the same signed label, so this commit removes
unnecessary logic and updates the UUU install script to support the new boot
artifact naming. It also fixes the detection of signed artifacts by checking
for the presence of the FIP artifact, instead of relying on a U-BOOT artifact
that does not exist on this platform.
https://onedigi.atlassian.net/browse/DEL-9442
Signed-off-by: Arturo Buzarra <arturo.buzarra@digi.com>
c59a5fdfe9