Perf: Make flingboost/scrollboost configurable for various msm

Flingboost and scrollboost is now controlled through a
variable, which can be set in a config.xml file.
Also it takes various parameters that could be msm
specific and are required to be set through target
specific config.xml.

Change-Id: Ida9381ec5a7561fbc73c5761afd474272446b0a2