ARM: dts: sun7i: Change cubietruck wifi enable pin to use mmc-pwrseq

The wifi-enable pin of the ap6210 module is not really a regulator,
switch to the mmc-pwrseq framework for controlling it. This more
accurately reflects how the hardware actually works.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[maxime: Changed the name of the pinctrl node and re-ordered it]
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>