mtd: Add armflash support for multiple blocks of flash

This patch adds MTD concatenation support to integrator-flash.c for
platforms with more than one block of flash memory (e.g. RealView
PB11MPCore). The implementation is based on the sa1100-flash.c one.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>