man: conditionalize sd-pcrlock and sd-measure on the same variable as their binaries

man: conditionalize sd-pcrlock and sd-measure on the same variable as their binaries

The binaries are built and installed if HAVE_TPM2 is set, and ignore ENABLE_BOOTLOADER,
so do the same for the manpages.

For the sd-pcrlock case this also installs the manpage aliases for the units, which
are not installed with -Dbootloader=disabled, but there's no way to conditionalize
the aliases, so on balance it's better to have too much documentation rather than
too little.

Fixes https://github.com/systemd/systemd/issues/30588