pinctrl: sunxi: Disable strict mode for old pinctrl drivers

Old pinctrl drivers will need to disable strict mode for various reasons,
among which:
  - Some DT will still have a pinctrl group for each GPIO used, which will
    be rejected by pin_request. While we could remove those nodes, we still
    have to deal with old DTs.
  - Some GPIOs on these boards need to have their pin configuration changed
    (for bias or current), and there's no clear migration path

Let's disable the strict mode on those SoCs so that there's no breakage.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>