Fix output cropping in vp9_get_preview_raw_frame.

Handle the non-420 case and set uv_width.

This is needed to get the correct colorspace information out of
vp9e_get_preview().

Change-Id: I62ce118cd7082708d812deb0843c1be87582e0fe

vp9/encoder/vp9_onyx_if.c

diff --git a/vp9/encoder/vp9_onyx_if.c b/vp9/encoder/vp9_onyx_if.c
index 42d4196..59d36ee 100644
--- a/vp9/encoder/vp9_onyx_if.c
+++ b/vp9/encoder/vp9_onyx_if.c
@@ -3689,7 +3689,8 @@
       *dest = *cpi->common.frame_to_show;
       dest->y_width = cpi->common.width;
       dest->y_height = cpi->common.height;
-      dest->uv_height = cpi->common.height / 2;
+      dest->uv_width = cpi->common.width >> cpi->common.subsampling_x;
+      dest->uv_height = cpi->common.height >> cpi->common.subsampling_y;
       ret = 0;
     } else {
       ret = -1;