Add a serdev controller driver for tty ports.
The controller is registered with serdev when tty ports are registered
with the TTY core. As the TTY core is built-in only, this has the side
effect of making serdev built-in as well.
Signed-off-by: Rob Herring
Reviewed-By: Sebastian Reichel
Tested-By: Sebastian Reichel
Signed-off-by: Greg Kroah-Hartman