dt-bindings: phy: Drop unneeded quotes

Cleanup bindings dropping unneeded quotes. Once all these are fixed,
checking for this can be enabled in yamllint.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> # for ti,tcan104x-can.yaml
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20230320233955.2921179-1-robh@kernel.org


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