Add binder call tetherOffloadSetInterfaceQuota

Provide binder calls for setting the limit for the given upstream
interface.

Bug: 150736748
Test: atest
Change-Id: I5def133022ee0ae232972c9ccffccd041b4b47a6
Merged-In: I5def133022ee0ae232972c9ccffccd041b4b47a6
diff --git a/server/TetherController.h b/server/TetherController.h
index 513a659..f8d6941 100644
--- a/server/TetherController.h
+++ b/server/TetherController.h
@@ -108,6 +108,8 @@
     base::Result<void> addOffloadRule(const TetherOffloadRuleParcel& rule);
     base::Result<void> removeOffloadRule(const TetherOffloadRuleParcel& rule);
 
+    int setTetherOffloadInterfaceQuota(int ifIndex, int64_t maxBytes);
+
     class TetherStats {
       public:
         TetherStats() = default;