Revert "Move Inet[4]AddressUtils to libs/net"

This reverts commit cf86031c12405ddb5817cf834c49a032480547b3.

Reason for revert: Breaks the build b/160390899

Merged-In: Icd141a992c46290c74929785e261a1cd57bc001b
Change-Id: Ie10e66f61393602f17fbb61bf17230b176bf1f44
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 8af1797..a61fcfb 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -19,14 +19,13 @@
 import static android.net.RouteInfo.RTN_UNICAST;
 import static android.net.TetheringManager.TetheringRequest.checkStaticAddressConfiguration;
 import static android.net.dhcp.IDhcpServer.STATUS_SUCCESS;
+import static android.net.shared.Inet4AddressUtils.intToInet4AddressHTH;
 import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
 import static android.net.util.NetworkConstants.asByte;
 import static android.net.util.PrefixUtils.asIpPrefix;
 import static android.net.util.TetheringMessageBase.BASE_IPSERVER;
 import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
 
-import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTH;
-
 import android.net.INetd;
 import android.net.INetworkStackStatusCallback;
 import android.net.IpPrefix;