ARM: mach-shmobile: specify sh7372 MIPI DSI register layout

Prepare the ap4evb board for the MIPI DSI driver transition to support

different register layouts.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>