Fix the SHJPEG_JPU_LINEBUFFER_PITCH value for images of up to 4092 pixels width

JPU can decode or encode up to 4092x4092 pixels of images.
Optimize the line buffer mode with larger buffers

This makes outout buffers larger to reduce the number of
switching JPU and VIO processings in the line buffer mode.
The switching may have overheads because of synchronization
of each processing completion through UIO.
Merge pull request #8 from matsu/master

[GIT PULL] Optimize the line buffer mode