goldfish: tty driver

This provides a console driver for the Goldfish virtual platform. The original
is from Arve with changes from Jun Nakajima and Tom Keel. This has been then
been ported to the current kernel and to the tty port mechanism by Alan Cox.
In the process it gained proper POSIX semantics and vhangup works. The default
name is not ttyS as this belongs to the 8250 driver. Instead ttyGFx is now used.

In the normal usage case the first port serves as a kernel logging console and
the second one carries various other data streams for the emulation.

Signed-off-by: Arve Hjønnevåg <arve@google.com>
[Cleaned up to handle x86]
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
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>
[Moved to 3.7 and chunks rewritten to use tty_port layer]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>