Camera: Add lock_buffer to preview_stream_ops

Giving HAL control of locking buffer instead of locking in dequeue buffer.

Change-Id: I2640b784218fa67ccb051c13b24f2d3dda48ce9a
Signed-off-by: Iliyan Malchev <malchev@google.com>
diff --git a/include/hardware/camera.h b/include/hardware/camera.h
index 4db6ad7..b47e011 100644
--- a/include/hardware/camera.h
+++ b/include/hardware/camera.h
@@ -105,9 +105,10 @@
                 int left, int top, int right, int bottom);
     int (*set_usage)(struct preview_stream_ops* w, int usage);
     int (*set_swap_interval)(struct preview_stream_ops *w, int interval);
-
     int (*get_min_undequeued_buffer_count)(const struct preview_stream_ops *w,
                 int *count);
+    int (*lock_buffer)(struct preview_stream_ops* w,
+                buffer_handle_t* buffer);
 } preview_stream_ops_t;
 
 struct camera_device;