MIPS: Ci20: Add support for rootfs on NFS to defconfig

Now that ethernet support is in the kernel, add the option to use a
rootfs over NFS to enable automated testing of upstream kernels on a
Ci20.

Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Harvey Hunt <harveyhuntnexus@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17314/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/configs/ci20_defconfig

@@ -38,6 +38,8 @@ CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y
 CONFIG_INET=y
+CONFIG_IP_PNP=y
+CONFIG_IP_PNP_DHCP=y
 # CONFIG_INET_XFRM_MODE_TRANSPORT is not set
 # CONFIG_INET_XFRM_MODE_TUNNEL is not set
 # CONFIG_INET_XFRM_MODE_BEET is not set
@@ -110,7 +112,8 @@ CONFIG_PROC_KCORE=y
 CONFIG_TMPFS=y
 CONFIG_CONFIGFS_FS=y
 CONFIG_UBIFS_FS=y
-# CONFIG_NETWORK_FILESYSTEMS is not set
+CONFIG_NFS_FS=y
+CONFIG_ROOT_NFS=y
 CONFIG_NLS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_CODEPAGE_737=y