ARM: 6986/1: mach-realview: add TCM support for PB1176

Enable TCM support on the RealView PB1176 - we have now taken
the precautions necessary to support even multi-board builds of
RealView systems with TCM enabled.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>