udoo_neo: Add Ethernet support

UDOO Neo boards has one FEC port connected to KSZ8091, add support for it.

Tested on a UDOO Neo Full with "dhcp zImage" command.

Signed-off-by: Breno Lima <breno.lima@nxp.com>
diff --git a/configs/udoo_neo_defconfig b/configs/udoo_neo_defconfig
index f88820c..5df4ef9 100644
--- a/configs/udoo_neo_defconfig
+++ b/configs/udoo_neo_defconfig
@@ -19,7 +19,7 @@
 CONFIG_CMD_MMC=y
 CONFIG_CMD_GPIO=y
 # CONFIG_CMD_SETEXPR is not set
-# CONFIG_CMD_DHCP=y
+CONFIG_CMD_DHCP=y
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_TIME=y
 CONFIG_CMD_EXT2=y