vf_fade: fix permissions.

libavfilter/vf_fade.c

@@ -290,8 +290,7 @@ AVFilter avfilter_vf_fade = {
                                           .start_frame      = ff_null_start_frame,
                                           .draw_slice      = draw_slice,
                                           .end_frame       = end_frame,
-                                          .min_perms       = AV_PERM_READ | AV_PERM_WRITE,
-                                          .rej_perms       = AV_PERM_PRESERVE, },
+                                          .min_perms       = AV_PERM_READ | AV_PERM_WRITE },
                                         { .name = NULL}},
     .outputs   = (const AVFilterPad[]) {{ .name            = "default",
                                           .type            = AVMEDIA_TYPE_VIDEO, },