eth: dm: fec: Change FEC PHY mask setting from CONFIG_PHYLIB to CONFIG_FEC_MXC_PHYADDR

Without this commit we do have an explicit dependency on CONFIG_PHYLIB
when one wants to set PHY ADDR on a iMX board (FEC + driver model).

This shall be changed to CONFIG_FEC_MXC_PHYADDR, as only when we do have
it set, we shall mask out other devices.

As a side effect, when CONFIG_FEC_MXC_PHYADDR is not set, we scan PHY bus
for connected PHY devices.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
diff --git a/drivers/net/fec_mxc.c b/drivers/net/fec_mxc.c
index 0076d63..f21fd44 100644
--- a/drivers/net/fec_mxc.c
+++ b/drivers/net/fec_mxc.c
@@ -1230,7 +1230,7 @@
 	struct phy_device *phydev;
 	int mask = 0xffffffff;
 
-#ifdef CONFIG_PHYLIB
+#ifdef CONFIG_FEC_MXC_PHYADDR
 	mask = 1 << CONFIG_FEC_MXC_PHYADDR;
 #endif