dt-bindings: pinctrl: mediatek: Fix child node name patterns

dt-bindings: pinctrl: mediatek: Fix child node name patterns

The child node name patterns in Mediatek pinctrl bindings don't match
reality. I don't know where '-[0-9]+$' came from, but I don't see any nodes
with a matching pattern. Also, patterns such as 'pins' or 'mux' are
ambiguous because any prefix or suffix is allowed. If that's desired, it
should be explicit.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230120020536.3229300-1-robh@kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>