net: phy: micrel: Add KSZ8041FTL fiber mode support

We can't detect the FXEN (fiber mode) bootstrap pin, so configure
it via a boolean device tree property "micrel,fiber-mode".
If it is enabled, auto-negotiation is not supported.
The only available modes are 100base-fx (full duplex and half duplex).

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/micrel_phy.h b/include/linux/micrel_phy.h
index 2e5b194..257173e 100644
--- a/include/linux/micrel_phy.h
+++ b/include/linux/micrel_phy.h
@@ -37,6 +37,7 @@
 
 /* struct phy_device dev_flags definitions */
 #define MICREL_PHY_50MHZ_CLK	0x00000001
+#define MICREL_PHY_FXEN		0x00000002
 
 #define MICREL_KSZ9021_EXTREG_CTRL	0xB
 #define MICREL_KSZ9021_EXTREG_DATA_WRITE	0xC