cpufreq: cpu-boost: Support separate input_boost_freq for different CPUs

Different types of CPUs could have different frequency to satisfy same
input workload. Add support for using different input_boost_freq on
different CPUs.

input_boost_freq now either takes a single number which applies to all
CPUs, or cpuid:freq pairs separated by space for different CPUs.

Change-Id: I20506a9fbdb4d532d94168bbd61744595bebc8e5
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
[avilaj@codeaurora.org: Change to sysfs from module param]
Signed-off-by: Jonathan Avila <avilaj@codeaurora.org>