drivers: cpufreq: add support for scaling available frequencies

this patch implements sysfs for scaling
between available cpu frequencies

also, it sets a safe limits during boot process

min: 200MHz
max: 1400|1600MHz

Change-Id: I7ddb7e2f0a5f88b05f8433ef0732c0fed23ec94e
Signed-off-by: Humberto Borba <humberos@gmail.com>
Merge "drivers: cpufreq: add support for scaling available frequencies" into du44