tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver

[Greg KH]

On Thu, May 19, 2011 at 08:34:52AM -0000, Timur Tabi wrote:
> The ePAPR embedded hypervisor specification provides an API for "byte
> channels", which are serial-like virtual devices for sending and receiving
> streams of bytes.  This driver provides Linux kernel support for byte
> channels via three distinct interfaces:
> 
> 1) An early-console (udbg) driver.  This provides early console output
> through a byte channel.  The byte channel handle must be specified in a
> Kconfig option.
> 
> 2) A normal console driver.  Output is sent to the byte channel designated
> for stdout in the device tree.  The console driver is for handling kernel
> printk calls.
> 
> 3) A tty driver, which is used to handle user-space input and output.  The
> byte channel used for the console is designated as the default tty.
> 
> Signed-off-by: Timur Tabi <timur at freescale.com>

Doesn't apply at all to the tty-next tree, so I can't apply it here :(