RealView: Add support for the Cortex-A8 Platform Baseboard

This patch adds support for RealView/PB-A8, a platform based on
Cortex-A8 with support for PCI-E and compact flash.

Signed-off-by: Bahadir Balban <bahadir.balban@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>