[KA06] export keepalive offload permission as system api.

Bug: 114151147
Test: m -j
Change-Id: I67a1656ccd3b0498d712c3a1297cf49ef8069eda
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 2f3c1db..bc5ec49 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -1554,7 +1554,7 @@
     <permission android:name="android.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS"
         android:protectionLevel="signature|privileged" />
 
-    <!-- Allows a system application to access hardware packet offload capabilities.
+    <!-- @SystemApi Allows a system application to access hardware packet offload capabilities.
          @hide -->
     <permission android:name="android.permission.PACKET_KEEPALIVE_OFFLOAD"
         android:protectionLevel="signature|privileged" />