msm: camera: sensor: add ref count logic for camera sensor subdev

some 3rd-part APP such as Gstreamer will cause sensor probe status
not correct and therefor camera App failed to open camera.
Add v4l2_subdev_intenal_ops open function for camera sensor
for open counter,Do not call internal_ops->close() every time
when call cam_req_mgr_close() so that open/close count for sensor
sub_dev driver can match each other.

CRs-Fixed: 2688114
Change-Id: I46318251e7ce1ed513bb57e0d72f95dfea22a77b
Signed-off-by: taojiang <taojiang@codeaurora.org>