net: fix mask for phy Micrel KSZ9031

Signed-off-by: Stefano Babic <sbabic@denx.de>
diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index a7450f8..f3e3054 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -174,7 +174,7 @@
 static struct phy_driver ksz9031_driver = {
 	.name = "Micrel ksz9031",
 	.uid  = 0x221620,
-	.mask = 0xfffffe,
+	.mask = 0xfffff0,
 	.features = PHY_GBIT_FEATURES,
 	.config   = &genphy_config,
 	.startup  = &ksz90xx_startup,