linux: move performance setup completly to '02_cpupower', setup up_threshold for ondemand

Signed-off-by: Stephan Raue <stephan@openelec.tv>
linux: dont build and install 'cpupower', can be done via /sys

Signed-off-by: Stephan Raue <stephan@openelec.tv>
bcm2835-driver: only install needed libraries

Signed-off-by: Stephan Raue <stephan@openelec.tv>