serial_txx9: use %lx for iobase

Fix a warning caused by commit 0c8946d97ae7d2d6691f8290a10faa63453b63f8
(serial: Make uart_port's ioport "unsigned long".)

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Josip Rodin <joy@entuzijast.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>