Relocated idct/add calls for encoder

Relocated idct/add calls for encoder

Call the idct/add after the tokenize.  This is WIP with
the goal of creating a common idct/add for the encoder and
decoder. This move is necessary because the decoder's version
of the idct clobbers qcoeff, which is used by the tokenize.

Change-Id: I6b08d8e8397cd873647fa4fb9469884e3c876756