x86, VisWS: turn into generic arch, update include/asm-x86/mach-visws/smpboot_hooks.h

update include/asm-x86/mach-visws/smpboot_hooks.h to
include/asm-x86/mach-default/smpboot_hooks.h (the generic version).

this _should_ work, because VISWS sets skip_ioapic_setup, but it
should be tested on a real VISWS to make sure.

Signed-off-by: Ingo Molnar <mingo@elte.hu>