media: tegra_camera: add start streaming call

media: tegra_camera: add start streaming call

Queueing buffer might happen before starting streaming. So any queueing
buffer operation before starting streaming shouldn't trigger real
capture but just queue the buffer. After starting streaming, it will
wake up kernel workqueue to start real capture.

Bug 1639982

Change-Id: I66fd527bbd12790b2d688f320214976e70a658f3
Signed-off-by: Bryan Wu <pengw@nvidia.com>
Reviewed-on: http://git-master/r/754710
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: David Wang (SW-TEGRA) <davidw@nvidia.com>
Reviewed-by: Winnie Hsu <whsu@nvidia.com>