goldfish: platform device for x86

Based on code by Jun Nakajima but stripped of all the old x86 mach-foo
stuff and turned into a single file for the Goldfish virtual bus layer.

The actual created platform device and bus enumeration is portable between the
ARM and x86 Goldfish emulations.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Link: http://lkml.kernel.org/r/20130121172205.19517.22535.stgit@bob.linux.org.uk
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Xiaohui Xin <xiaohui.xin@intel.com>
Signed-off-by: Jun Nakajima <jun.nakajima@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
[Ported to 3.7 and reorganised so that we can keep most of the code
 shared properly]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>