avcodec/mpeg4videodec: fix 'libavcodec/mpeg4videodec.c:2762:22: warning: unused variable mpeg4_vdpau_class [-Wunused-const-variable]'

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpeg4videodec.c

@@ -2759,13 +2759,6 @@ static const AVClass mpeg4_class = {
     LIBAVUTIL_VERSION_INT,
 };
 
-static const AVClass mpeg4_vdpau_class = {
-    "MPEG4 Video VDPAU Decoder",
-    av_default_item_name,
-    mpeg4_options,
-    LIBAVUTIL_VERSION_INT,
-};
-
 AVCodec ff_mpeg4_decoder = {
     .name                  = "mpeg4",
     .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
@@ -2788,6 +2781,13 @@ AVCodec ff_mpeg4_decoder = {
 
 
 #if CONFIG_MPEG4_VDPAU_DECODER
+static const AVClass mpeg4_vdpau_class = {
+    "MPEG4 Video VDPAU Decoder",
+    av_default_item_name,
+    mpeg4_options,
+    LIBAVUTIL_VERSION_INT,
+};
+
 AVCodec ff_mpeg4_vdpau_decoder = {
     .name           = "mpeg4_vdpau",
     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),