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>