Sunix Multi I/O boards are different to Timedia's.

This patch adds proper support for Sunix MIO boards with 1 parallel and
up to 4 serial ports.

Cc: Morris Ku <morris_ku@sunix.com>
Cc: Debbie Liu <debbie_liu@sunix.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20190809190130.30773-2-kai.heng.feng@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>