Fix NV12, and NV21 format descriptors

Also adds support for YU12 pixel format that is used in video frames

Change-Id: I613beef8b3e2296fd1fab7e2b9d2956fba1ac788
diff --git a/android/camera/camera-capture-linux.c b/android/camera/camera-capture-linux.c
index 50324f0..895690d 100644
--- a/android/camera/camera-capture-linux.c
+++ b/android/camera/camera-capture-linux.c
@@ -123,6 +123,7 @@
 static const uint32_t _preferred_formats[] =
 {
     /* Native format for the emulated camera: no conversion at all. */
+    V4L2_PIX_FMT_YUV420,
     V4L2_PIX_FMT_YVU420,
     /* Continue with YCbCr: less math than with RGB */
     V4L2_PIX_FMT_NV12,