powerpc: mpc8641hpcn: Enable DHCP command and DDR debug

Enable DHCP command to make TFTP easier.
Enable DDR interactive debug by default.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/configs/MPC8641HPCN_defconfig b/configs/MPC8641HPCN_defconfig
index 64fe8e4..aa2a464 100644
--- a/configs/MPC8641HPCN_defconfig
+++ b/configs/MPC8641HPCN_defconfig
@@ -10,6 +10,7 @@
 CONFIG_CMD_I2C=y
 CONFIG_CMD_USB=y
 # CONFIG_CMD_SETEXPR is not set
+CONFIG_CMD_DHCP=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_EXT2=y
 CONFIG_DOS_PARTITION=y