ARM: meson: Fix refcount leak in meson_smp_prepare_cpus

of_find_compatible_node() returns a node pointer with refcount
incremented, we should use of_node_put() on it when done.
Add missing of_node_put() to avoid refcount leak.

Fixes: d850f3e5

 ("ARM: meson: Add SMP bringup code for Meson8 and Meson8b")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20220512021611.47921-1-linmq006@gmail.com