Performance improvement of first pass

Improved the performance of the first pass only
(~6% on 720p test clip) by making use of LUT instead of the
float calculations.  Might try a SIMD version later.
Also started to make use of int_mv instead of
MV.

Change-Id: If2a217c7d6b59cd2c25c5553e0ca7e0502403af8
1 file changed