Remove ksvc_fixed_mode from aom_svc_params_t

Remove the ksvc_fixed_mode field from the aom_svc_params_t struct. The
aom_svc_params_t struct is a public struct that libaom clients allocate
and pass to aom_codec_control(AV1E_SET_SVC_PARAMS), so changing the
definition of the aom_svc_params_t struct breaks binary compatibility.

Note: This CL reverts only this part of Marco's commit:
    rtc-svc: Allow for fixed SVC modes
    https://aomedia-review.googlesource.com/c/aom/+/133868
The rest of that commit is preserved.

BUG=aomedia:3032

Change-Id: I69a0a339333f8302c18f8e25f49c0cd4840a174b
diff --git a/aom/aomcx.h b/aom/aomcx.h
index 3291f33..cb37f59 100644
--- a/aom/aomcx.h
+++ b/aom/aomcx.h
@@ -1459,8 +1459,6 @@
   int layer_target_bitrate[AOM_MAX_LAYERS];
   /*! Frame rate factor for each temporal layer */
   int framerate_factor[AOM_MAX_TS_LAYERS];
-  /*! Flag to do KSVC for fixed mode */
-  int ksvc_fixed_mode;
 } aom_svc_params_t;
 
 /*!brief Parameters for setting ref frame config */
diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index 7f3c10b..11c9249 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -2938,7 +2938,6 @@
   cm->number_temporal_layers = params->number_temporal_layers;
   cpi->svc.number_spatial_layers = params->number_spatial_layers;
   cpi->svc.number_temporal_layers = params->number_temporal_layers;
-  cpi->svc.ksvc_fixed_mode = params->ksvc_fixed_mode;
   if (cm->number_spatial_layers > 1 || cm->number_temporal_layers > 1) {
     unsigned int sl, tl;
     cpi->use_svc = 1;
diff --git a/examples/svc_encoder_rtc.c b/examples/svc_encoder_rtc.c
index eed4679..44bed38 100644
--- a/examples/svc_encoder_rtc.c
+++ b/examples/svc_encoder_rtc.c
@@ -1272,8 +1272,8 @@
     svc_params.scaling_factor_num[1] = 1;
     svc_params.scaling_factor_den[1] = 2;
   }
-  svc_params.ksvc_fixed_mode = 0;  // Set to 1 to do KSVC in fixed mode.
   aom_codec_control(&codec, AV1E_SET_SVC_PARAMS, &svc_params);
+  // TODO(aomedia:3032): Configure KSVC in fixed mode.
 
   // This controls the maximum target size of the key frame.
   // For generating smaller key frames, use a smaller max_intra_size_pct
diff --git a/test/svc_datarate_test.cc b/test/svc_datarate_test.cc
index 995ff24..d2839cc 100644
--- a/test/svc_datarate_test.cc
+++ b/test/svc_datarate_test.cc
@@ -89,8 +89,8 @@
     if (video->frame() == 0) {
       initialize_svc(number_temporal_layers_, number_spatial_layers_,
                      &svc_params_);
-      svc_params_.ksvc_fixed_mode = 0;
       encoder->Control(AV1E_SET_SVC_PARAMS, &svc_params_);
+      // TODO(aomedia:3032): Configure KSVC in fixed mode.
       encoder->Control(AV1E_SET_ENABLE_ORDER_HINT, 0);
       encoder->Control(AV1E_SET_ENABLE_TPL_MODEL, 0);
       encoder->Control(AV1E_SET_DELTAQ_MODE, 0);