remoteproc: qcom_q6v5_pas: Fix missing of_node_put() in adsp_alloc_memory_region()

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

Fixes: b9e718e9

 ("remoteproc: Introduce Qualcomm ADSP PIL")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221203070639.15128-1-yuancan@huawei.com