ARM: SMDK6410: Configure GPIO pull up for WM835x IRQ line

When used with the WM1190-EV1 board we can use the internal pull up
resistor of the CPU to provide the required pull for the IRQ line.
Without this interrupts from the WM835x don't work in the default
WM1190-EV1 hardwaer configuration.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>