ARM: 7461/1: topology: Add arch_scale_freq_power function

Add infrastructure to be able to modify the cpu_power of each core

Change-Id: Ibb1e3669162348128ec2abe3f9d8c6396a32893e
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>