PM / devfreq: bw_hwmon: Remove unused tunables and disable some by default

With the rewrite of the algorithm, some tunables are not used. Remove those
tunables. Other tunables don't make a lot of sense to be turned on by
default. Change their default state to be disabled.

Change-Id: I228d275a21765986a7117b335a669deebf590f29
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>