Fix cpupower manpages "NAME" section

The token before "-" should be the program name, no spaces allowed.
See man(7) and lexgrog(1).

Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Thomas Renninger <trenn@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>