Use cleanup to manage mutex. Let compiler to do scope guard automatically.

Fixes: 6aa60f79 ("dmaengine: fsl-edma: add safety check for 'srcid'")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202404110915.riwV3ZAC-lkp@intel.com/Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240411203935.3137158-1-Frank.Li@nxp.comSigned-off-by: Vinod Koul <vkoul@kernel.org>