dt-bindings: pinctrl: ralink: {mt7620,mt7621}: rename to mediatek

Rename schemas of pin controllers for MediaTek MT7620 and MT7621 SoCs to be
on par with other pin controllers for MediaTek SoCs.

Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230317213011.13656-10-arinc.unal@arinc9.com


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