cpupower: update German translation

Update the German translation of cpupower, and change the encoding
to UTF-8.

[skhan@linuxfoundation.org: fix merge conflicts]
Signed-off-by: Benjamin Weis <benjamin.weis@gmx.com>
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>