Add YV12 preview format to camera parameter constants.

bug:3463624
Change-Id: I8f2992dadfd3fb9e3c9d67743e52da7f3212827e
diff --git a/libs/camera/CameraParameters.cpp b/libs/camera/CameraParameters.cpp
index e9a5f8c..0fd79a4 100644
--- a/libs/camera/CameraParameters.cpp
+++ b/libs/camera/CameraParameters.cpp
@@ -132,10 +132,10 @@
 const char CameraParameters::SCENE_MODE_CANDLELIGHT[] = "candlelight";
 const char CameraParameters::SCENE_MODE_BARCODE[] = "barcode";
 
-const char CameraParameters::PIXEL_FORMAT_YUV420P[]  = "yuv420p";
 const char CameraParameters::PIXEL_FORMAT_YUV422SP[] = "yuv422sp";
 const char CameraParameters::PIXEL_FORMAT_YUV420SP[] = "yuv420sp";
 const char CameraParameters::PIXEL_FORMAT_YUV422I[] = "yuv422i-yuyv";
+const char CameraParameters::PIXEL_FORMAT_YUV420P[]  = "yuv420p";
 const char CameraParameters::PIXEL_FORMAT_RGB565[] = "rgb565";
 const char CameraParameters::PIXEL_FORMAT_JPEG[] = "jpeg";