x86: change size of node ids from u8 to u16

Change the size of node ids from 8 bits to 16 bits to
accomodate more than 256 nodes.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>