net: mpc8xx_fec: Migrate to DM_ETH

Migrate mpc8xx_fec driver to DM_ETH.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/configs/MCR3000_defconfig b/configs/MCR3000_defconfig
index 086507e..94743d6 100644
--- a/configs/MCR3000_defconfig
+++ b/configs/MCR3000_defconfig
@@ -91,3 +91,4 @@
 CONFIG_WDT=y
 CONFIG_SHA256=y
 CONFIG_LZMA=y
+CONFIG_DM_ETH=y