Set row_mt to 0 by default

Set row_mt to 0 for now.

Change-Id: I922536a6d71a765e435daeaf4d932ef14363d19a

vp9/vp9_cx_iface.c

@@ -84,7 +84,7 @@ static struct vp9_extracfg default_extra_cfg = {
   0,                     // color range
   0,                     // render width
   0,                     // render height
-  1,                     // row_mt
+  0,                     // row_mt
   0,                     // row_mt_bit_exact
 };