Fix a spatial svc test crash

Fixes crash in 2pass spatial svc test that was introduced in:
https://chromium-review.googlesource.com/#/c/313571/6

Change-Id: Iab3e8225a8d159cd33f5849dffe6802e25038047

vpx/src/svc_encodeframe.c

@@ -423,13 +423,15 @@ vpx_codec_err_t vpx_svc_init(SvcContext *svc_ctx, vpx_codec_ctx_t *codec_ctx,
     svc_ctx->temporal_layers = 2;
   }
 
+  for (sl = 0; sl < VPX_SS_MAX_LAYERS; ++sl) {
+    si->svc_params.scaling_factor_num[sl] = DEFAULT_SCALE_FACTORS_NUM[sl];
+    si->svc_params.scaling_factor_den[sl] = DEFAULT_SCALE_FACTORS_DEN[sl];
+  }
   for (tl = 0; tl < svc_ctx->temporal_layers; ++tl) {
     for (sl = 0; sl < svc_ctx->spatial_layers; ++sl) {
       i = sl * svc_ctx->temporal_layers + tl;
       si->svc_params.max_quantizers[i] = MAX_QUANTIZER;
       si->svc_params.min_quantizers[i] = 0;
-      si->svc_params.scaling_factor_num[sl] = DEFAULT_SCALE_FACTORS_NUM[sl];
-      si->svc_params.scaling_factor_den[sl] = DEFAULT_SCALE_FACTORS_DEN[sl];
     }
   }