clang-error: fix clang-diagnostic-inconsistent-missing-override error

This clang-error is generated when a function overrides a member
function but is not marked 'override'.

Change-Id: I664941c2dff5be93dec1571cc974fae2168925f2
Signed-off-by: Pavithra Barithaya <pavithra.b@ibm.com>
diff --git a/pldmtool/oem/ibm/pldm_oem_ibm.cpp b/pldmtool/oem/ibm/pldm_oem_ibm.cpp
index 100857e..db2b63a 100644
--- a/pldmtool/oem/ibm/pldm_oem_ibm.cpp
+++ b/pldmtool/oem/ibm/pldm_oem_ibm.cpp
@@ -109,7 +109,7 @@
     }
 
     void parseResponseMsg(pldm_msg*, size_t) override {}
-    void exec()
+    void exec() override
     {
         std::vector<uint8_t> requestMsg(sizeof(pldm_msg_hdr) +
                                         PLDM_GET_FILE_TABLE_REQ_BYTES);