vp10_encoder: add missing vpx_clear_system_state

Mirror the fix in vp9_encoder for sse-only build.

Change-Id: I9f272874e52f4cc295fcaa71920f8a5d3a80045b

vp10/encoder/encoder.c

diff --git a/vp10/encoder/encoder.c b/vp10/encoder/encoder.c
index 1d69cd0..1eab6a3 100644
--- a/vp10/encoder/encoder.c
+++ b/vp10/encoder/encoder.c
@@ -4547,6 +4547,7 @@
         cpi->svc.spatial_layer_to_encode = 0;
     }
   }
+  vpx_clear_system_state();
   return 0;
 }