msm: camera: Send VFE_REG_UPDATE_CMD while enabling liveshot.

Sometimes, especially with YUV sensors, snapshot frame is
not received in time when liveshot is triggered.

CRs-Fixed: 501466
Change-Id: Ib92929ebe82eadb92492d899b2077832fab02842

Signed-off-by: Sai Kumar Sanagavarapu <ssanagav@codeaurora.org>
Signed-off-by: Sridhar Gujje <sgujje@codeaurora.org>