x86/devicetree: Use CPU description from Device Tree

Current x86 Device Tree implementation does not support multiprocessing.
Use new DT bindings to describe the processors.

Signed-off-by: Ivan Gorinov <ivan.gorinov@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Link: https://lkml.kernel.org/r/c291fb2cef51b730b59916d7745be0eaa4378c6c.1521753738.git.ivan.gorinov@intel.com