phy: add missing constants for Micrel KSZ9031

Signed-off-by: Stefano Babic <sbabic@denx.de>

include/micrel.h

@@ -15,6 +15,11 @@
 #define MII_KSZ9031_MOD_DATA_POST_INC_RW	0x8000
 #define MII_KSZ9031_MOD_DATA_POST_INC_W		0xC000
 
+#define MII_KSZ9031_EXT_RGMII_CTRL_SIG_SKEW	0x4
+#define MII_KSZ9031_EXT_RGMII_RX_DATA_SKEW	0x5
+#define MII_KSZ9031_EXT_RGMII_TX_DATA_SKEW	0x6
+#define MII_KSZ9031_EXT_RGMII_CLOCK_SKEW	0x8
+
 struct phy_device;
 int ksz9021_phy_extended_write(struct phy_device *phydev, int regnum, u16 val);
 int ksz9021_phy_extended_read(struct phy_device *phydev, int regnum);