msm: wfd:Wait for one more vsync cycle, if VSG running out of input frames

If VSG running out of input frames, it will re-encode previous frames.
With this change, instead of encoding pervious frame VSG will push timer to
half of capturing frame rate. If it find new frame, it will be encoded
Otherwise will re-encode previous frame.

CRs-Fixed: 571771
Change-Id: Ie1c970b4e251c2165e77134b746c4ee0e3a90fba
Signed-off-by: Srinu Gorle <sgorle@codeaurora.org>