ucNumDeltaPocsOfRefRpsIdx needs to contain the flat value from the SPS RPS,
and not the final computed value from the slice header RPS, as this calculation
is done internally by the driver again.

Sample-Id: http://trailers.divx.com/hevc/Sintel_4k_27qp_24fps_1aud_9subs.mkviSigned-off-by: Rémi Denis-Courmont <remi@remlab.net>