hwpstate_amd(4): Factor out printing CPPC registers, fix CPPC_REQUEST's

Factor out these printing, so they can be called from other places than
just the register dump handler. This also makes surrounding code
clearer.

Fix inverted printing of minimum and maximum performance.

For better diagnostic, print the full raw content of each register
before printing the value of fields we know about.

As fields are printed in decimal, remove 0-padding, which could give the
impression that the numbers are printed in octal or hexadecimal.

While here, remove superfluous blank lines when printing (we use TABs
for the different registers' fields).

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D54999