x86, VisWS: turn into generic arch, create include/asm-x86/visws/

move the include/asm-x86/mach-visws/ VISWS specific hardware
details include files into include/asm-x86/visws, to be used from
generic code.

No code changed.

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