Bug fix: set frame_parallel_decoding_mode

This patch allows the frame_parallel_decoding_mode flag
to be set instead of returning a codec error.

Change-Id: I4a1631c625723ac8873290d0fd0211074a87d112

vp9/vp9_cx_iface.c

@@ -1032,6 +1032,7 @@ static vpx_codec_ctrl_fn_map_t vp9e_ctf_maps[] = {
   {VP8E_SET_CQ_LEVEL,                 set_param},
   {VP8E_SET_MAX_INTRA_BITRATE_PCT,    set_param},
   {VP9E_SET_LOSSLESS,                 set_param},
+  {VP9E_SET_FRAME_PARALLEL_DECODING,  set_param},
   {VP9_GET_REFERENCE,                 get_reference},
   { -1, NULL},
 };