Introduce vSMP arch to the kernel.

This patch:
1. Adds CONFIG_X86_VSMP
2. Adds machine specific macros for local_irq_disabled, local_irq_enabled
   and irqs_disabled
3. Writes to the vSMP CTL device to indicate kernel compiled with CONFIG_VSMP
Signed-off-by: NRavikiran Thirumalai <kiran@scalemp.com>
Signed-off-by: NShai Fultheim <shai@scalemp.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>