omxil: Avoid warnings about differences in signedness

For omxil, the nal size has already been parsed out elsewhere, so
we don't need it returned here.

This fixes this warning:
omxil.c:926: warning: pointer targets in passing argument 7 of 'convert_sps_pps' differ in signedness
h264_nal.h:22: note: expected 'uint32_t *' but argument is of type 'int *'
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/codec/omxil/omxil.c

@@ -926,8 +926,7 @@ static int OpenGeneric( vlc_object_t *p_this, bool b_encode )
             p_header->nFilledLen = 0;
             convert_sps_pps( p_dec, p_dec->fmt_in.p_extra, p_dec->fmt_in.i_extra,
                              p_header->pBuffer, p_header->nAllocLen,
-                             (uint32_t*) &p_header->nFilledLen,
-                             &p_sys->i_nal_size_length );
+                             (uint32_t*) &p_header->nFilledLen, NULL );
         }
         else if(p_sys->in.b_direct)
         {