msm: kgsl: Add disable-busy-time-burst to disable ceiling threshold

Add a devicetree property disable-busy-time-burst to
disable ceiling threshold in the governor. The ceiling threshold
cause busy time burst that switch power level for
large frames based on busy time.

Change-Id: I44f8a51e0aa49bb0b2210703f57874fd5f219c18
Signed-off-by: Divya Ponnusamy <pdivya@codeaurora.org>