Running Codeql on MdeModulePkg/Universal/SmmCommunicationBuffer drivers results in codeql errors stemming from missing null tests. Signed-off-by: Aaron Pop <aaronpop@microsoft.com> Co-authored-by: Michael Kubacki <michael.kubacki@microsoft.com> Co-authored-by: Taylor Beebe <tabeebe@microsoft.com> Co-authored-by: pohanch <125842322+pohanch@users.noreply.github.com> Co-authored-by: kenlautner <85201046+kenlautner@users.noreply.github.com> Co-authored-by: Oliver Smith-Denny <osde@linux.microsoft.com> Co-authored-by: Sean Brogan <sean.brogan@microsoft.com> Co-authored-by: Aaron <aaronpop@microsoft>