ARM: vexpress: create A5 specific board config

This patch creates a new config for the A5 dual core tile that includes the
generic config for the Versatile Express platform.

The generic config has been modified to provide support for the Extended
Memory Map, as used on the A5 core tile.  A5 does not support the legacy
memory map.

Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@linaro.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 8fb01ef..15bfdfe 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -968,6 +968,7 @@
 Matt Waddel <matt.waddel@linaro.org>
 
 	vexpress_ca9x4	ARM ARMV7 (Quad Core)
+	vexpress_ca5x2	ARM ARMV7 (Dual Core)
 
 Otavio Salvador <otavio@ossystems.com.br>