ppc/km: convert KM_DEF_NETDEV to Kconfig

Remove this from the board header files and move it to Kconfig. Also use
the correct default address for kmtegr1.

Signed-off-by: Holger Brunck <holger.brunck@ch.abb.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
CC: Priyanka Jain <priyanka.jain@nxp.com>
CC: Valentin Longchamp <valentin.longchamp@ch.abb.com>
diff --git a/configs/kmtegr1_defconfig b/configs/kmtegr1_defconfig
index 91b7aa8..e014f7e 100644
--- a/configs/kmtegr1_defconfig
+++ b/configs/kmtegr1_defconfig
@@ -1,5 +1,6 @@
 CONFIG_PPC=y
 CONFIG_SYS_TEXT_BASE=0xF0000000
+CONFIG_KM_DEF_NETDEV="eth1"
 CONFIG_ENV_SIZE=0x4000
 CONFIG_SYS_BOOTCOUNT_ADDR=0xE0113FF8
 CONFIG_ENV_SECT_SIZE=0x20000