Revert "Always use the 16-bit coding path"

BUG=aomedia:620

This reverts commit 4da880bd2be22d5c89af43e880e426e094061256.

Change-Id: I40a2295083b3328ef743d3eab9c2aa514dc698eb
diff --git a/configure b/configure
index fb889cf..f59bf05 100755
--- a/configure
+++ b/configure
@@ -507,6 +507,9 @@
     # Backwards/jenkins compatibility with --enable-aom-highbitdepth
     enabled aom_highbitdepth && enable_feature highbitdepth
 
+    # Enable low-bitdepth pixel pipeline by default
+    soft_enable lowbitdepth
+
     soft_enable palette
     soft_enable alt_intra
     soft_enable palette_throughput