dt-bindings: pinctrl: rt2880: fix binding name, pin groups and functions

Deprecate the old property "ralink,rt2880-pinmux". Add the new property
"ralink,rt2880-pinctrl". The old property name was inaccurate as the
hardware block is called pinctrl across the Mediatek/Ralink architecture.

Current pin group and function bindings are for MT7621. Put bindings for
RT2880 instead.

Add me as a maintainer.

Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20220414173916.5552-11-arinc.unal@arinc9.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>