This provides a new API allows different OLPC architectures to override the
EC driver.  x86 and ARM OLPC machines use completely different EC backends.

The olpc_ec_cmd is synchronous, and waits for the workqueue to send the
command to the EC.  Multiple callers can run olpc_ec_cmd() at once, and
they will by serialized and sleep while only one executes on the EC at a time.

We don't provide an unregister function, as that doesn't make sense within
the context of OLPC machines - there's only ever 1 EC, it's critical to
functionality, and it certainly not hotpluggable.
Signed-off-by: NAndres Salomon <dilinger@queued.net>
Acked-by: NPaul Fox <pgf@laptop.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

The OLPC EC driver has outgrown arch/x86/platform/.  It's time to both
share common code amongst different architectures, as well as move it out
of arch/x86/.  The XO-1.75 is ARM-based, and the EC driver shares a lot of
code with the x86 code.
Signed-off-by: NAndres Salomon <dilinger@queued.net>
Acked-by: NPaul Fox <pgf@laptop.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>