Platform: OLPC: Move EC-specific functionality out from x86

Move the olpc-ec driver away from the X86 OLPC platform so that it could be
used by the ARM based laptops too. Notably, the driver for the OLPC battery,
which is also used on the ARM models, builds on this driver's interface.

It is actually plaform independent: the OLPC EC commands with their argument
and responses are mostly the same despite the delivery mechanism is
different.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>