hwpmc_logging: less macro magic for type names

Provide the log type names in their entirely, rather than relying on the
macro to prepend the prefix. This improves their searchability; for
example, if I see PMCLOG_TYPE_PMCALLOCATE in libpmc I will now be able
to find where that is emitted in the kernel with a simple grep.

Reviewed by: jkoshy, emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D39911