lavf/vaapi_deinterlace: return error if mode unsupported

Reviewed-by: NMark Thompson <sw@jkqxz.net>
Signed-off-by: NFuwei Tang <fuweix.tang@intel.com>
Signed-off-by: NZhong Li <zhong.li@intel.com>

libavfilter/vf_deinterlace_vaapi.c

@@ -113,6 +113,7 @@ static int deint_vaapi_build_filter_params(AVFilterContext *avctx)
             av_log(avctx, AV_LOG_ERROR, "Deinterlacing mode %d (%s) is "
                    "not supported.\n", ctx->mode,
                    deint_vaapi_mode_name(ctx->mode));
+            return AVERROR(EINVAL);
         }
     }