irqchip/gic/realview: Support more RealView DCC variants

In the add-on file for the GIC dealing with the RealView family
we currently only handle the PB11MPCore, let's extend this to
manage the RealView EB ARM11MPCore as well. The Revision B of the
ARM11MPCore core tile is a bit special and needs special handling
as it moves a system control register around at random.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: devicetree@vger.kernel.org
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>