dt-bindings: phy: fsl,imx8mq-usb: Drop 'db' suffix duplicating dtschema

A common property unit suffix '-db' was added to dtschema, thus
in-kernel bindings should not reference the type.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250811-dt-bindings-db-v1-2-457301523bb5@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>