[ARM] 3334/1: Add support for IXDP28x5 platforms

Patch from Deepak Saxena

This patch adds support for Intel's IXDP28x5 platform. This
is just and IXDP2801 with a new CPU rev but the bootloader
has been updated to reflect a new machine ID so we just build
support for it by default when we build IXDP2801.

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