pinctrl: xway: drop the deprecated compatible strings

This code are marked as deprecated since kernel 4.5[1]. Downstream OpenWRT
and upstream switched to the new string compatible 7 years ago. The old
compatible strings can safely be dropped.

[1] commit be14811c ("pinctrl/lantiq: introduce new dedicated devicetree bindings")
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Link: https://lore.kernel.org/r/20230330212225.10214-1-olek2@wp.plSigned-off-by: Linus Walleij <linus.walleij@linaro.org>