Move hidden APIs into system APIs

To allow vendor code to construct LinkAddress, which is
one of the parameter in the system API DataCallResponse.

Test: Build
Bug: 73659459
Merged-In: I3e203781d3a03285fa0e047cc8837ccb4a09016a
Change-Id: I3e203781d3a03285fa0e047cc8837ccb4a09016a
diff --git a/core/java/android/net/LinkAddress.java b/core/java/android/net/LinkAddress.java
index 1bc0d32..77562db 100644
--- a/core/java/android/net/LinkAddress.java
+++ b/core/java/android/net/LinkAddress.java
@@ -25,6 +25,7 @@
 import static android.system.OsConstants.RT_SCOPE_SITE;
 import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
 
+import android.annotation.SystemApi;
 import android.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -167,7 +168,7 @@
      * @param prefixLength The prefix length.
      * @hide
      */
-    @UnsupportedAppUsage
+    @SystemApi
     public LinkAddress(InetAddress address, int prefixLength) {
         this(address, prefixLength, 0, 0);
         this.scope = scopeForUnicastAddress(address);
@@ -190,7 +191,7 @@
      * @param string The string to parse.
      * @hide
      */
-    @UnsupportedAppUsage
+    @SystemApi
     public LinkAddress(String address) {
         this(address, 0, 0);
         this.scope = scopeForUnicastAddress(this.address);