dmaengine: ti: Add missing put_device in ti_dra7_xbar_route_allocate

of_find_device_by_node() takes reference, we should use put_device()
to release it when not need anymore.

Fixes: a074ae38

 ("dmaengine: Add driver for TI DMA crossbar on DRA7x")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Link: https://lore.kernel.org/r/20220605042723.17668-1-linmq006@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>