dt-bindings: mfd: Correct interrupt flags in examples

GPIO_ACTIVE_x flags are not correct in the context of interrupt flags.
These are simple defines so they could be used in DTS but they will not
have the same meaning:
1. GPIO_ACTIVE_HIGH = 0 = IRQ_TYPE_NONE
2. GPIO_ACTIVE_LOW  = 1 = IRQ_TYPE_EDGE_RISING

Correct the interrupt flags, assuming the author of the code wanted same
logical behavior behind the name "ACTIVE_xxx", this is:
  ACTIVE_LOW => IRQ_TYPE_LEVEL_LOW

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> # for BD70528
Acked-by: Tim Harvey <tharvey@gateworks.com> # for gateworks-gsc.yaml
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>