phy: amlogic: meson-g12a-usb2: fix Wvoid-pointer-to-enum-cast warning

'soc_id' is an enum, thus cast of pointer on 64-bit compile test with
W=1 causes:

  phy-meson-g12a-usb2.c:322:17: error: cast to smaller integer type 'enum meson_soc_id' from 'const void *' [-Werror,-Wvoid-pointer-to-enum-cast]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230810091310.70231-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>