Platform: OLPC: move global variables into priv struct

Populate olpc_ec_priv with variables that were previously global.  This
makes things a tad bit clearer, IMO.

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