usb: dwc3: st: use scoped device node handling to simplify error paths

Obtain the device node reference with scoped/cleanup.h to reduce error
handling and make the code a bit simpler.  Scoped/cleanup.h coding style
expects variable declaration with initialization, so the
of_get_compatible_child() call has to be moved earlier, before any goto
jumps happen.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://lore.kernel.org/r/20240814-b4-cleanup-h-of-node-put-usb-v1-1-95481b9682bc@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>