Add return stmt after av1_resize_horz_dir_c() call

Otherwise we will fall through and execute code that assumes
filtered_length >= 16.

Bug: aomedia:3575
Change-Id: I88385f0d30fd6f9392b828d8bf716f7cc6f3b6b3
diff --git a/av1/common/x86/resize_sse2.c b/av1/common/x86/resize_sse2.c
index 1afc962..6b34ceb 100644
--- a/av1/common/x86/resize_sse2.c
+++ b/av1/common/x86/resize_sse2.c
@@ -194,6 +194,7 @@
   if (filtered_length < 16) {
     av1_resize_horz_dir_c(input, in_stride, intbuf, height, filtered_length,
                           width2);
+    return;
   }
 
   __m128i coeffs_x[2];