[PATCH] Serial: Add support for SIIG Quartet serial card

Add support for SIIG Quartet Serial card.  This card has Oxford
Semiconducor 16954 quad UART which is clocked by 10x faster
(18.432 MHz) quartz.

Signed-off-by: Andrey Panin <pazke@donpac.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>