Change to fourcc to enable decoding of ffmpeg files.

Change-Id: Ia16f167d904d53bc38cb3a8c841c6c52daad500f
(cherry picked from commit 296421d84cd1ffd074ff3fe4a772238c897f1bda)
reverts: dbd050c vpxdec: correct VP[89] fourccs
diff --git a/vpxdec.c b/vpxdec.c
index df0b819..41c654f 100644
--- a/vpxdec.c
+++ b/vpxdec.c
@@ -49,8 +49,8 @@
 
 static const char *exec_name;
 
-#define VP8_FOURCC (0x30385056)
-#define VP9_FOURCC (0x30395056)
+#define VP8_FOURCC (0x00385056)
+#define VP9_FOURCC (0x00395056)
 static const struct {
   char const *name;
   const vpx_codec_iface_t *(*iface)(void);