ARM: 8363/1: sa1100: use ioremapped memory to access SC registers

Use ioremap() and readl/writel_relaxed() to access IRQ controller
registers.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>