firmware: psci: Fix refcount leak in psci_dt_init

firmware: psci: Fix refcount leak in psci_dt_init

Fix a reference counter leak in psci_dt_init() where of_node_put(np) was
missing after of_find_matching_node_and_match() when np is unavailable.

Fixes: d09a0011ec0d ("drivers: psci: Allow PSCI node to be disabled")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20250318151712.28763-1-linmq006@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>