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>