Fix a spatial svc assert failure

Fixes spatial svc rc assert failure introdcued in:
https://chromium-review.googlesource.com/#/c/312959/1

Change-Id: I6096bfbc484859d71a5fb55e6a3248a31885af61

vp9/encoder/vp9_svc_layercontext.c

diff --git a/vp9/encoder/vp9_svc_layercontext.c b/vp9/encoder/vp9_svc_layercontext.c
index 13da155..b0617c1 100644
--- a/vp9/encoder/vp9_svc_layercontext.c
+++ b/vp9/encoder/vp9_svc_layercontext.c
@@ -279,7 +279,7 @@
   // Reset the frames_since_key and frames_to_key counters to their values
   // before the layer restore. Keep these defined for the stream (not layer).
   if (cpi->svc.number_temporal_layers > 1 ||
-      cpi->svc.number_spatial_layers > 1) {
+      (cpi->svc.number_spatial_layers > 1 && !is_two_pass_svc(cpi))) {
     cpi->rc.frames_since_key = old_frame_since_key;
     cpi->rc.frames_to_key = old_frame_to_key;
   }