Change our dhcp interface to be IPv6 compat.

Doesn't do IPv6, but removes v4-specific structures from the framework
(netmask, ints for addrs)
bug:2542681

Change-Id: I1110e6f32d42a472b104835a4298e18b391db0a7
diff --git a/include/netutils/dhcp.h b/include/netutils/dhcp.h
index 96798c5..bd16240 100644
--- a/include/netutils/dhcp.h
+++ b/include/netutils/dhcp.h
@@ -24,12 +24,12 @@
 
 extern int do_dhcp(char *iname);
 extern int dhcp_do_request(const char *ifname,
-                          in_addr_t *ipaddr,
-                          in_addr_t *gateway,
-                          in_addr_t *mask,
-                          in_addr_t *dns1,
-                          in_addr_t *dns2,
-                          in_addr_t *server,
+                          char *ipaddr,
+                          char *gateway,
+                          uint32_t *prefixLength,
+                          char *dns1,
+                          char *dns2,
+                          char *server,
                           uint32_t  *lease);
 extern int dhcp_stop(const char *ifname);
 extern int dhcp_release_lease(const char *ifname);