fbdev: SuperH Mobile LCDC Driver

This is the SuperH Mobile LCDC frame buffer driver V2, adding support for
the LCDC block found in SuperH Mobile processors.  The hardware supports
up to two LCD panels per LCDC block, and both RGB and SYS interfaces can
be used to hook up LCD panels/modules.

The device driver is a regular platform driver, so LCD configuration and
board specific hooks are passed to the driver using platform data.  LCD
modules using SYS interface often require special configuration using the
SYS bus, and to solve this cleanly the driver provides SYS interface
operations to the board code.

Tested on sh7723 and sh7722 processors with a SYS16A QVGA panel and WVGA
panels using RGB16 and RGB18 interfaces.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Reviewed-by: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>