phy: constify of_phandle_args in xlate

The xlate callbacks are supposed to translate of_phandle_args to proper
provider without modifying the of_phandle_args.  Make the argument
pointer to const for code safety and readability.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com> #Broadcom
Link: https://lore.kernel.org/r/20240217093937.58234-1-krzysztof.kozlowski@linaro.org


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