cpufreq: cpu-boost: Unify input and hotplug boost

* This doesn't make sense to have mirror functions
  operating different boost frequencies.
* If input_boost_freq > hotplug_boost_freq, hotplug
  boost will be rendered useless in most case since
  parallel input boost will be doing it work.
* So instead having separate boost functions,
  keep only single boost function "do_input_boost"
  and let hotplug callback access this boost.
* Disable hotplug boost by default and provide
  attribute for same.

* Increased migration_load_threshold to prevent
  not-so-needed and recurring migrations.

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

Conflicts:
	drivers/cpufreq/cpu-boost.c
cpufreq: cpu-boost: Do not consider keypad events for boost

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>