boot,stub: explicitly measure select SMBIOS objects (#42233)

boot,stub: explicitly measure select SMBIOS objects (#42233)

This is supposed to protect our SMBIOS type 11 importing for
credentials. Note that firmwares are supposed to measure SMBIOS anyway
to PCR 1. Alas firmware doesn't really do that in various cases. Hence
let's do so again, for select objects.

This closes a gap where some of the input for OS (i.e. system
credentials places in smbios11) isn't measured properly.

(I really want this to get into v261, because this will fuck up the PCRs
a bit more, and we already have the new separator measurement in v261,
hence there's value in getting this merged at the same time, so that we
don't break the measurements a 2nd time)