video: ARM CLCD: support Nomadik variant

The Nomadik variant has a few special quirks that need to be respected
to make the driver work:

- The block need to be clocked during writing of the TIMn registers
  or the bus will stall.
- Special bits in the control register select how many of the output
  display lines get activated.
- Special bits in the control register select how to manage the
  different 565 and 5551 modes.
- There is a packed 24bit graphics mode, i.e 888 pixels can be stored
  in memory is three consecutive bytes, not evenly aligned to a 32bit
  word.

This patch uses the vendor data pointer from the AMBA matching mechanism
to track the quirks for this variant, and adds two hooks that variants
can use to initialize boards and panels during start-up. These will
later be used to adopt a Nomadik board profile.

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>