uart8250io: Unify calls with generic UART

Change-Id: I6d56648e56f2177e1d5332497321e718df18300c
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5234
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
7 files changed