cpufreq: interactive: Ramp up to policy->max for heavy new task

New tasks don't have sufficient history to predict its behavior, even
with scheduler's help. Ramping up conservatively for a heavy task
could hurt performance when it's needed. Therefore, separate out new
tasks' load with scheduler's help and ramp up more aggressively if new
tasks make up a significant portion of total load.

Change-Id: Ia95c956369edb9b7a0768f3bdcb0b2fab367fdf7
Suggested-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>