realtek: add missing of.h include in phy driver

of.h is required for of_property_read_u32().

Signed-off-by: INAGAKI Hiroshi <[email protected]>
[amend commit message]
Signed-off-by: Sander Vanheule <[email protected]>

target/linux/realtek/files-5.10/drivers/net/phy/rtl83xx-phy.c

@@ -6,6 +6,7 @@
 
 #include <linux/module.h>
 #include <linux/delay.h>
+#include <linux/of.h>
 #include <linux/phy.h>
 #include <linux/netdevice.h>
 #include <linux/firmware.h>