Fix configurable U-Boot attempt setting
Fix configurable U-Boot attempt setting

Commit ebbdb4be9d ("Make U-Boot attempt settings configurable") made
it possible to tweak the number of attempts that are set in the U-Boot
environment.

There is an issue with that because U-Boot's setexpr can only handle
hex, while in the current implementation those values are treated as
decimals.

To work around that, let's treat those numbers as hex everywhere.

Signed-off-by: Pascal Huerst <bfd2b3f3fb15f048a4f3c4169c34c7c8ce18b9d3@gmail.com>

rauc/rauc,jluebbe/rauc,rauc/rauc,jluebbe/rauc,ejoerns/rauc,jluebbe/rauc,ejoerns/rauc,ejoerns/rauc,rauc/rauc