remoteproc: qcom: Fix missing of_node_put in adsp_alloc_memory_region

The device_node pointer is returned by of_parse_phandle()  with refcount
incremented. We should use of_node_put() on it when done.

Fixes: dc160e44 ("remoteproc: qcom: Introduce Non-PAS ADSP PIL driver")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220308031219.4718-1-linmq006@gmail.com