bootX measurements and measurement API moved to u-boot core:

Up to now, U-Boot could perform measurements and EventLog creation as
described by the TCG spec when booting via EFI.

The EFI code was residing in lib/efi_loader/efi_tcg2.c and contained
both EFI specific code + the API needed to access the TPM, extend PCRs
and create an EventLog. The non-EFI part proved modular enough and
moving it around to the TPM subsystem was straightforward.

With that in place we can have a common API for measuring binaries
regardless of the boot command, EFI or boot(m|i|z), and contructing an
EventLog.

I've tested all of the EFI cases -- booting with an empty EventLog and
booting with a previous stage loader providing one and found no
regressions.  Eddie tested the bootX part.

Eddie also fixed the sandbox TPM which couldn't be used for the EFI code
and it now supports all the required capabilities. This had a slight
sideeffect in our...