Revert "tty: of_serial: add support for the DesignWare 8250"

This reverts commit 14a8d47d

.

It causes a build error that needs to be resolved differently.

Cc: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>