Platform: OLPC: add a suspended flag to the EC driver

A problem we've noticed on XO-1.75 is when we suspend in the middle of
an EC command.  Don't allow that.

In the process, create a private object for the generic EC driver to use;
we have a framework for passing around a struct, use that rather than a
proliferation of global variables.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: Paul Fox <pgf@laptop.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>