lavfi: add priv_class for some forgotten filters.

This allows to print the options available when using commands such as
ffmpeg -help full.

libavfilter/f_ebur128.c

@@ -747,4 +747,5 @@ AVFilter avfilter_af_ebur128 = {
     .query_formats = query_formats,
     .inputs        = ebur128_inputs,
     .outputs       = NULL,
+    .priv_class    = &ebur128_class,
 };

libavfilter/vf_delogo.c

@@ -283,4 +283,5 @@ AVFilter avfilter_vf_delogo = {
 
     .inputs    = avfilter_vf_delogo_inputs,
     .outputs   = avfilter_vf_delogo_outputs,
+    .priv_class = &delogo_class,
 };

libavfilter/vf_edgedetect.c

@@ -327,4 +327,5 @@ AVFilter avfilter_vf_edgedetect = {
     .query_formats = query_formats,
     .inputs        = edgedetect_inputs,
     .outputs       = edgedetect_outputs,
+    .priv_class    = &edgedetect_class,
 };

libavfilter/vsrc_mandelbrot.c

@@ -417,4 +417,5 @@ AVFilter avfilter_vsrc_mandelbrot = {
     .query_formats = query_formats,
     .inputs        = NULL,
     .outputs       = mandelbrot_outputs,
+    .priv_class    = &mandelbrot_class,
 };

libavfilter/vsrc_mptestsrc.c

@@ -384,4 +384,5 @@ AVFilter avfilter_vsrc_mptestsrc = {
 
     .inputs         = NULL,
     .outputs        = mptestsrc_outputs,
+    .priv_class     = &mptestsrc_class,
 };