avcodec/vdpau_hevc: Properly signal the num_delta_pocs from the SPS RPS

This is the same fix that Hendrik made to dxva2_hevc. It should be
equally required here, although I don't see any visual difference.
Nevertheless, best to stay consistent.

libavcodec/vdpau_hevc.c

@@ -213,7 +213,7 @@ static int vdpau_hevc_start_frame(AVCodecContext *avctx,
         /** Corresponds to specification field, NumDeltaPocs[RefRpsIdx].
             Only applicable when short_term_ref_pic_set_sps_flag == 0.
             Implementations will ignore this value in other cases. See 7.4.8. */
-        info->NumDeltaPocsOfRefRpsIdx = sh->short_term_rps->num_delta_pocs;
+        info->NumDeltaPocsOfRefRpsIdx = sh->short_term_rps->rps_idx_num_delta_pocs;
     }
     /** Section 7.6.3.1 of the H.265/HEVC Specification defines the syntax of
         the slice_segment_header. This header contains information that