vp9-rtc: Add control to disable maxq on overshoot

Add encoder control to disable feature to increase Q
on overshoot detection, for CBR. Default (no usage
of the control) means the feature is internally enabled.

Add the control to the sample encoders, but keep it
disabled as default (set to 0, so feature is on).

Change-Id: Ia2237bc4aaea9770e5080dab20bfff9e3fd09199

examples/vpx_temporal_svc_encoder.c

@@ -831,6 +831,7 @@ int main(int argc, char **argv) {
   } else if (strncmp(encoder->name, "vp9", 3) == 0) {
     vpx_svc_extra_cfg_t svc_params;
     memset(&svc_params, 0, sizeof(svc_params));
+    vpx_codec_control(&codec, VP9E_SET_DISABLE_OVERSHOOT_MAXQ_CBR, 0);
     vpx_codec_control(&codec, VP8E_SET_CPUUSED, speed);
     vpx_codec_control(&codec, VP9E_SET_AQ_MODE, 3);
     vpx_codec_control(&codec, VP9E_SET_GF_CBR_BOOST_PCT, 0);