ASoC: codecs: wcd939x: Add VDD_PX supply

Device has also VDD_PX supply, which should be acquired by the driver.
Regulator framework will provide a dummy supply, thus the change is
compatible with older DTS.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250526-b4-asoc-wcd9395-vdd-px-v1-6-64d3cb60313b@linaro.org


Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>