If --enable-ext-partition is used at build time, the superblock size
(sometimes also referred to as coding unit (CU) size) is extended to
128x128 pixels.
Change-Id: Ie09cec6b7e8d765b7555ff5d80974aab60803f3a
1) Add facade to quantize b/fp/dc version so that their interface
are the same.
2) Merge vp10_xform_quant b/fp/dc version to one function so that
the code flow in encodemb.c is clear
Change-Id: Ib62d6215438fc2d07f4e7e72393f964832d6746f
