Moxa serial boards only need a special setup function, we can use
generic 8250 framework for other parts.

So let's merge 8250_moxa to 8250_pci.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20190816165124.16942-1-kai.heng.feng@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>