soundwire: debugfs: simplify with cleanup.h

Allocate the memory with scoped/cleanup.h to reduce error handling and
make the code a bit simpler.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240703-soundwire-cleanup-h-v1-9-24fa0dbb948f@linaro.org


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