sh: add UIO support for JPU on SH7722.

Add JPU support on Migo-R via UIO. This make use of Magnus's
generic UIO platform driver. Chunk of contiguous memory to hold
intermediate image and compressed data during encode and decode.

Signed-off-by: Takanari Hayama <taki@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>