avplay: use the correct array size for stride.

AV_NUM_DATA_POINTERS instead of 4.

avplay.c

@@ -1527,7 +1527,7 @@ static int input_get_buffer(AVCodecContext *codec, AVFrame *pic)
     AVFilterContext *ctx = codec->opaque;
     AVFilterBufferRef  *ref;
     int perms = AV_PERM_WRITE;
-    int i, w, h, stride[4];
+    int i, w, h, stride[AV_NUM_DATA_POINTERS];
     unsigned edge;
     int pixel_size;