net: sungem_phy: Add of_node_put() for reference returned by of_get_parent()

[ Upstream commit ebbbe23f ]

In bcm5421_init(), we should call of_node_put() for the reference
returned by of_get_parent() which has increased the refcount.

Fixes: 3c326fe9

 ("[PATCH] ppc64: Add new PHY to sungem")
Signed-off-by: Liang He <windhl@126.com>
Link: https://lore.kernel.org/r/20220720131003.1287426-1-windhl@126.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>