x86: geode: New PCEngines Alix system driver

This new driver replaces the old PCEngines Alix 2/3 LED driver with a
new driver that controls the LEDs through the leds-gpio driver. The
old driver accessed GPIOs directly, which created a conflict and
prevented also loading the cs5535-gpio driver to read other GPIOs on
the Alix board. With this new driver, we hook into leds-gpio which in
turn uses GPIO to control the LEDs and therefore it's possible to
control both the LEDs and access onboard GPIOs

Driver is moved to platform/geode as requested by Grant and any other
geode initialisation modules should move here also

This driver is inspired by leds-net5501.c by Alessandro Zummo.

Ideally, leds-net5501.c should also be moved to platform/geode. 
Additionally the driver relies on parts of the patch: 7f131cf3 ("leds:
leds-alix2c - take port address from MSR) by Daniel Mack to perform
detection of the Alix board.

[akpm@linux-foundation.org: include module.h]

Signed-off-by: Ed Wildgoose <kernel@wildgooses.com>
Cc: git@wildgooses.com
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Reviewed-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>