cpupower: AMD fam14h/Ontario monitor can also be used by fam12h cpus

The name of the monitor is updated at runtime to the name of the
CPU type.

Signed-off-by: Thomas Renninger <trenn@suse.de>
CC: Andreas Herrmann <herrmann.der.user@googlemail.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>