mfd: tqmx86: Clear GPIO IRQ resource when no IRQ is set

The driver was registering IRQ 0 when no IRQ was set. This leads to
warnings with newer kernels.

Clear the resource flags, so no resource is registered at all in this
case.

Fixes: 2f17dd34 ("mfd: tqmx86: IO controller with I2C, Wachdog and GPIO")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Lee Jones <lee.jones@linaro.org>