gpio: pl061: move platform data into driver

No boardfile defines any PL061 platform data anymore: the
Integrator IM/PD-1 includes the file but is not making use
of the struct. Let's delete the include and all references,
then move the platform data into the driver for later
consolidation into the driver state container.

The only resource defined by the IM/PD-1 is the IRQ which
is passed through the AMBA PrimeCell bus abstraction
struct amba_device.

Cc: arm@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>