dmaengine: xilinx_dma: cleanup for fetching xlnx,num-fstores property

Free the allocated resources for missing xlnx,num-fstores property.

Signed-off-by: Swati Agarwal <swati.agarwal@xilinx.com>
Link: https://lore.kernel.org/r/20220817061125.4720-3-swati.agarwal@xilinx.com


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