dt-bindings: i2c: i2c-wmt: Convert to YAML

dt-bindings: i2c: i2c-wmt: Convert to YAML

Rewrite the textual description for the WonderMedia I2C controller
as YAML schema, and switch the filename to follow the compatible
string.

The controller only supports two bus speeds (100kHz and 400kHz)
so restrict clock-frequency values accordingly.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Alexey Charkov <alchark@gmail.com>
Link: https://lore.kernel.org/r/20250506-vt8500-i2c-binding-v3-1-401c3e090a88@gmail.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>