msm: vidc: Fix scale clocks based on cycles/mb

Existing video driver scales Venus clocks either based
on a static load-freq table or it determines the load
from cycles/mb and computes the freq. Scalability of
Venus clock was decided based on the number of entries
in static load-freq table. So incases when the load-freq
table is not present, the driver assumes that the
clocks are not scalable. Due to this, all the Venus
clocks were prepared for lowest frequency and were
not scaled later during the video session.
The code fixes the scaling of Venus clock and makes
both the scaling approach mutually exclusive.

Change-Id: Ia8e4bea236d5f94e717041a3517d35c69c0e4619
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>