cpupower: Remove unneeded code and by that fix a memleak

Looks like some not needed debug code slipped in.
Also this code:
tmp = sysfs_get_idlestate_name(cpu, idlestates - 1);
performs a strdup and the mem was not freed again.
-> delete it.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>