Obtain the device node reference with scoped/cleanup.h to reduce error
handling and make the code a bit simpler.

Unlike in other typical of_node_get+syscon_node_to_regmap cases, the
reference cannot be dropped immediately after syscon_node_to_regmap(),
because further part of probe() uses it.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240826-phy-of-node-scope-v1-8-5b4d82582644@linaro.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>