Mark struct member as final in IaPdOption and IaPrefixOption.

Bug: 271797628
Test: m
Change-Id: I6b4ae9e9b4011f705831eec48ebab813ab5911b6
diff --git a/staticlibs/device/com/android/net/module/util/structs/IaPdOption.java b/staticlibs/device/com/android/net/module/util/structs/IaPdOption.java
index 5a09c40..dbf79dc 100644
--- a/staticlibs/device/com/android/net/module/util/structs/IaPdOption.java
+++ b/staticlibs/device/com/android/net/module/util/structs/IaPdOption.java
@@ -50,15 +50,15 @@
     public static final int LENGTH = 12; // option length excluding IA_PD options
 
     @Field(order = 0, type = Type.S16)
-    public short code;
+    public final short code;
     @Field(order = 1, type = Type.S16)
-    public short length;
+    public final short length;
     @Field(order = 2, type = Type.U32)
-    public long id;
+    public final long id;
     @Field(order = 3, type = Type.U32)
-    public long t1;
+    public final long t1;
     @Field(order = 4, type = Type.U32)
-    public long t2;
+    public final long t2;
 
     IaPdOption(final short code, final short length, final long id, final long t1,
             final long t2) {
diff --git a/staticlibs/device/com/android/net/module/util/structs/IaPrefixOption.java b/staticlibs/device/com/android/net/module/util/structs/IaPrefixOption.java
index 1ac21ff..cd974e6 100644
--- a/staticlibs/device/com/android/net/module/util/structs/IaPrefixOption.java
+++ b/staticlibs/device/com/android/net/module/util/structs/IaPrefixOption.java
@@ -55,17 +55,17 @@
     public static final int LENGTH = 25; // option length excluding IAprefix-options
 
     @Field(order = 0, type = Type.S16)
-    public short code;
+    public final short code;
     @Field(order = 1, type = Type.S16)
-    public short length;
+    public final short length;
     @Field(order = 2, type = Type.U32)
-    public long preferred;
+    public final long preferred;
     @Field(order = 3, type = Type.U32)
-    public long valid;
+    public final long valid;
     @Field(order = 4, type = Type.U8)
-    public short prefixLen;
+    public final short prefixLen;
     @Field(order = 5, type = Type.ByteArray, arraysize = 16)
-    public byte[] prefix;
+    public final byte[] prefix;
 
     IaPrefixOption(final short code, final short length, final long preferred,
             final long valid, final short prefixLen, final byte[] prefix) {