libavfilter: vf_split from soc.

Commited by michael, for detailed authorship see soc repo

libavfilter/allfilters.c

@@ -68,6 +68,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (SETTB,       settb,       vf);
     REGISTER_FILTER (SHOWINFO,    showinfo,    vf);
     REGISTER_FILTER (SLICIFY,     slicify,     vf);
+    REGISTER_FILTER (SPLIT,       split,       vf);
     REGISTER_FILTER (TRANSPOSE,   transpose,   vf);
     REGISTER_FILTER (UNSHARP,     unsharp,     vf);
     REGISTER_FILTER (VFLIP,       vflip,       vf);