dmaengine: fsl-edma: change to guard(mutex) within fsl_edma3_xlate()

Introduce a scope guard to automatically unlock the mutex within
fsl_edma3_xlate() to simplify the code.

Prepare to add source ID checks in the future.

Signed-off-by: Joy Zou <joy.zou@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240701070232.2519179-2-joy.zou@nxp.com


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