soc: amlogic: add missing of_node_put()

The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented here after the last
usage.

Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Fixes: d4983983 ("soc: amlogic: add meson-canvas driver")
Signed-off-by: Kevin Hilman <khilman@baylibre.com>