video: driver: fix usage of v4l2_fh

- Do not clear V4L2_FL_USES_V4L2_FH flag because this
  flag indicates that file->private_data points to
  &struct v4l2_fh.
- Initialize v4l2 ctrl handler with driver ctrl handler.
- Add ctrl ops for g_volatile_ctrl to return updated
  value of volatile ctrls from driver.
Fixes: v4l2-compliance:
		testPrio (VIDIOC_G/S_PRIORITY).
		testQueryControls (VIDIOC_QUERYCTRL).

Change-Id: Ibe4b6fa67d2c02a5afeb627f2060e4761c5ef717
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>

driver/vidc/inc/msm_vidc.h

@@ -25,10 +25,8 @@ int msm_vidc_s_selection(void* instance, struct v4l2_selection* s);
 int msm_vidc_g_selection(void* instance, struct v4l2_selection* s);
 int msm_vidc_s_param(void *instance, struct v4l2_streamparm *sp);
 int msm_vidc_g_param(void *instance, struct v4l2_streamparm *sp);
-int msm_vidc_s_ctrl(void *instance, struct v4l2_control *a);
 int msm_vidc_s_ext_ctrl(void *instance, struct v4l2_ext_controls *a);
 int msm_vidc_g_ext_ctrl(void *instance, struct v4l2_ext_controls *a);
-int msm_vidc_g_ctrl(void *instance, struct v4l2_control *a);
 int msm_vidc_reqbufs(void *instance, struct v4l2_requestbuffers *b);
 int msm_vidc_release_buffer(void *instance, int buffer_type,
 		unsigned int buffer_index);