Platform: OLPC: Remove an unused include

Also, the header is x86 specific, while there are non-x86 OLPC machines.

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>