soundwire: slave: fix an OF node reference leak in soundwire slave device

When initializing a soundwire slave device, an OF node is stored to the
device with refcount incremented. However, the refcount is not
decremented in .release(), thus call of_node_put() in
sdw_slave_release().

Fixes: a2e48458 ("soundwire: core: add device tree support for slave devices")
Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20241205034844.2784964-1-joe@pf.is.s.u-tokyo.ac.jp


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