dt-bindings: pinctrl: sunxi: Disallow the resets property

None of the sunxi pin controllers have a module reset line. This is
confirmed by documentation (A80) as well as experimentation (A33).

Since the property is not applicable to any variant of the hardware,
let's remove it from the binding.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220531053623.43851-4-samuel@sholland.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>