[ARM] 3600/1: increase amba-pl010 UART_NR to 8

Patch from Lennert Buytenhek

The cirrus ep93xx has 3 pl010 UARTs, while amba-pl010.c only allows
for 2 by default.  A while ago, I think we agreed on changing the 2
to 8, but I don't see this in 2.6.17 yet.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>