mfd: Don't try to flag IRQ 0 as a wm831x wake source

If we've not got a primary IRQ we shouldn't be trying to flag IRQ 0 as a
wake source.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
1 file changed