video: ARM CLCD: add special board and panel hooks for Nomadik

In the .board_init() callback will set up a mux register in
the Nomadik system controller. It so happens that the platform
has two display output engines, and we have to poke a bit in
a special register to make sure the right engine is muxed in
as they are mutually exclusive.

The Nomadik CLCD variant is instantiated on a platform where
it is combined with a 800x480 TPO WVGA display. In the
.panel_init() hook we will detect this display from the
compatible string and set it up. We also add .enable() and
.disable() callbacks for it as the sleep state is software
controlled.

The display is connected with a special 3-wire serial bus
(this is sadly neither I2C or SPI) using three GPIO lines that
we bitbang to detect the display and enable/disable sleep
state.

Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>