ath11k: add missing of_node_put() to avoid leak

The node pointer is returned by of_find_node_by_type()
or of_parse_phandle() with refcount incremented. Calling
of_node_put() to aovid the refcount leak.

Fixes: 6ac04bdc ("ath11k: Use reserved host DDR addresses from DT for PCI devices")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20211221114003.335557-1-yangyingliang@huawei.com