msm: vidc: Add RC timestamp disable control

Add and fix rate control timestamp disable control. WFD usecase
requires time delta calculation from input frame rate. Rest of
usecases calculate time delta based on buffer timestamp. Hence,
RC timestamp disable control is disabled by default.

Change-Id: I5652cdf96e0527968f6e0dabbc35df6a00817aa9
Signed-off-by: Amit Shekhar <ashekhar@codeaurora.org>