net: phy: micrel: make ksz9021 phy accessible

Micrel accidentally used the same part number
for the KS8721 and KSZ9021. So, both cannot be
in the same build of u-boot. Add a config option
to handle this.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>

include/configs/mx6qsabrelite.h

@@ -96,6 +96,7 @@
 #define CONFIG_FEC_MXC_PHYADDR		6
 #define CONFIG_PHYLIB
 #define CONFIG_PHY_MICREL
+#define CONFIG_PHY_MICREL_KSZ9021
 
 /* USB Configs */
 #define CONFIG_CMD_USB