soundwire: cadence: Remove ret variable from sdw_cdns_irq()

soundwire: cadence: Remove ret variable from sdw_cdns_irq()

The ret is not used in the interrupt handler, it is just returned without
any condition or change.
We can return the IRQ_HANDLED directly.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210714015555.17685-1-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>