bpf: switch to mainline netbpfload on Android S/SV2

Test: TreeHugger, manually installing tethering apex
  (with and without dnsresolver apex) on pixel 6 running S
  incl. 'atest bpf_existence_test'
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I63d4b84287e9c98dc0d2a517ac58d3f3ce9d7760
diff --git a/Tethering/apex/Android.bp b/Tethering/apex/Android.bp
index 19dd492..2878f79 100644
--- a/Tethering/apex/Android.bp
+++ b/Tethering/apex/Android.bp
@@ -102,15 +102,14 @@
         "dscpPolicy.o",
         "netd.o",
         "offload.o",
-        "offload@mainline.o",
         "test.o",
-        "test@mainline.o",
     ],
     apps: [
         "ServiceConnectivityResources",
     ],
     prebuilts: [
         "current_sdkinfo",
+        "netbpfload.31rc",
         "netbpfload.33rc",
         "netbpfload.35rc",
         "ot-daemon.34rc",