[ARM] 3388/1: ixp23xx: add core ixp23xx support

Patch from Lennert Buytenhek

This patch adds support for the Intel ixp23xx series of CPUs.  The
ixp23xx is an XSC3 based CPU with 512K of L2 cache, a 64bit 66MHz PCI
interface, two DDR RAM interfaces, QDR RAM interfaces, two gigabit
MACs, two 10/100 MACs, expansion bus, four microengines, a Media and
Switch Fabric unit almost identical to the one on the ixp2400, two
xscale (8250ish) UARTs and a bunch of other stuff.

This patch adds the core ixp23xx support code, and support for the
ADI Engineering Roadrunner, Intel IXDP2351, and IP Fabrics Double
Espresso platforms.

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