ARM: 6235/2: driver for the LEDs found in the later ARM refdesigns

This adds a simple driver supporting the new LED framework with
triggers and all for the RealView and Versatile platforms. The
RealView and Versatile platform drivers were arranged to compile
for all-but-integrator as a side effect since the Integrator has
a different LED driver.

Signed-off-by: Linus Walleij <triad@df.lth.se>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>