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

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.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/sungem_phy.c

@@ -450,6 +450,7 @@ static int bcm5421_init(struct mii_phy* phy)
 		int can_low_power = 1;
 		if (np == NULL || of_get_property(np, "no-autolowpower", NULL))
 			can_low_power = 0;
+		of_node_put(np);
 		if (can_low_power) {
 			/* Enable automatic low-power */
 			sungem_phy_write(phy, 0x1c, 0x9002);