[ARM] realview: Add support for Realview-EB-MPCore board

This patch adds support for Realview-EB-MPCore board in generic Realview board support.

The Realview-EB-MPCore is an ARMv6 board with ARM11 multiprocessor core (ARM11MP).

With this patch we are able to boot Xvisor on Realview-EB-MPCore emulated by QEMU.

Signed-off-by: Anup Patel <anup@brainfault.org>