libvpx: Pull from upstream

source/libvpx/vpx/svc_context.h

Index: source/libvpx/vpx/svc_context.h
diff --git a/source/libvpx/vpx/svc_context.h b/source/libvpx/vpx/svc_context.h
index cf791bdeb568ba0886430e4dcbfaebb2ed339ec0..a09651cc991540c64558b0ad1fbb1be03c7dc205 100644
--- a/source/libvpx/vpx/svc_context.h
+++ b/source/libvpx/vpx/svc_context.h
@@ -33,10 +33,13 @@ typedef struct {
   // public interface to svc_command options
   int spatial_layers;               // number of spatial layers
   int temporal_layers;               // number of temporal layers
+  int temporal_layering_mode;
   SVC_LOG_LEVEL log_level;  // amount of information to display
   int log_print;  // when set, printf log messages instead of returning the
                   // message with svc_get_message
-
+  int output_rc_stat;  // for outputting rc stats
+  int speed;  // speed setting for codec
+  int threads;
   // private storage for vpx_svc_encode
   void *internal;
 } SvcContext;