video: msm: wfd: Add turbo mode support

Add support for userspace to push the video core clock to maximum
supported by hardware.

Change-Id: Ida6618fd77bc24fe043885306083249546797054
CRs-Fixed: 361108
Signed-off-by: Srinu Gorle <sgorle@codeaurora.org>
[davidb: only include/linux/videodev2.h]
Signed-off-by: David Brown <davidb@codeaurora.org>