dev-arm: clang compatibility fix, added missing overrides

Change-Id: I5ee5ff788570178bb1d68878a26ac9e3ce636d8e
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19588
Reviewed-by: Matteo Andreozzi <matteo.andreozzi@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/src/dev/arm/smmu_v3_slaveifc.hh b/src/dev/arm/smmu_v3_slaveifc.hh
index 3302d82..5759a8f 100644
--- a/src/dev/arm/smmu_v3_slaveifc.hh
+++ b/src/dev/arm/smmu_v3_slaveifc.hh
@@ -116,7 +116,7 @@
         SMMUv3SlaveInterface,
         &SMMUv3SlaveInterface::atsSendDeviceRetry> atsSendDeviceRetryEvent;
 
-    Port& getPort(const std::string &name, PortID id);
+    Port& getPort(const std::string &name, PortID id) override;
 
   public:
     SMMUv3SlaveInterface(const SMMUv3SlaveInterfaceParams *p);