dt-bindings: nvmem: mediatek: add support for MediaTek MT7623 and MT7622 SoC

This updates dt-binding documentation for MediaTek MT7622 and
MT7623 SoC. For the both SoCs supported all rely on the fallback
binding of the generic case with "mediatek,efuse".

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>