arm64: a37xx: pinctrl: probe after binding

Currently, pinctrl drivers are getting probed during post-bind, however
that is being reverted, and on A37XX pinctrl driver is the one that
registers the GPIO driver during the probe.

So, if the pinctrl driver doesn't get probed GPIO-s won't get registered
and thus they cannot be used.

This is a problem on the Methode eDPU as it just uses SB pins as GPIO-s
and without them being registered networking won't work as it only has
one SFP slot and the TX disable GPIO is on the SB controller.

So, lets just add a flag only to A37XX driver to probe after binding
in order for the GPIO driver to always get registered.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Reviewed-by: Simon Glass <sjg@chromium.org>