It makes sense to use similar encoding for all three packages and so it
should be named as:
ara_00000126_00001001_fffe0001_ffe70018_s2l.tftf
Because the boot stage is passed from ES3 bootrom, we can't change its
value now. But the string created to match the package name is created
in bootrom.c and that is the only string we create from bootrom.c.
Update bootrom.c to use "s2l" instead of "02" in the package name.