[spatial svc] Fix one extra frame count during flush

Change-Id: Ia096aafa8aca4f9e58450c4b861393d8f0a15afe

vpx/src/svc_encodeframe.c

diff --git a/vpx/src/svc_encodeframe.c b/vpx/src/svc_encodeframe.c
index 76aacd2..38c2d26 100644
--- a/vpx/src/svc_encodeframe.c
+++ b/vpx/src/svc_encodeframe.c
@@ -1000,8 +1000,10 @@
               (int)si->frame_size, (int)pts);
     }
   }
-  ++si->frame_within_gop;
-  ++si->encode_frame_count;
+  if (rawimg != NULL) {
+    ++si->frame_within_gop;
+    ++si->encode_frame_count;
+  }
 
   return VPX_CODEC_OK;
 }