Reapply: "Enhance DHCP beyond just OFF and IPv4/IPv6 enabled."

DHCP is not a binary option.  The network interface can have DHCP
disabled, IPv4 only, IPv6 only, and IPv4/IPv6.

Signed-off-by: Johnathan Mantey <jonathanx.mantey@intel.com>

Reapplied ->
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Change-Id: I7654116aa3962de253225271190ce4a2fe229ce9
diff --git a/xyz/openbmc_project/Network/EthernetInterface.interface.yaml b/xyz/openbmc_project/Network/EthernetInterface.interface.yaml
index b18f6c7..b968106 100644
--- a/xyz/openbmc_project/Network/EthernetInterface.interface.yaml
+++ b/xyz/openbmc_project/Network/EthernetInterface.interface.yaml
@@ -23,7 +23,7 @@
       description: >
           Domain names of the ethernet interface.
     - name: DHCPEnabled
-      type: boolean
+      type: enum[self.DHCPConf]
       description: >
           Address mode of the ethernet interface.
     - name: Nameservers
@@ -82,4 +82,11 @@
         - name: v4
         - name: v6
         - name: none
-
+    - name: DHCPConf
+      description: >
+          A list of the permitted DHCP settings used by systemd.
+      values:
+        - name: both
+        - name: v4
+        - name: v6
+        - name: none