test: add missing headers to ipmi_interface_mock

Add missing header for the ipmi interface to the ipmi_interface_mock
header and the gmock header.

Change-Id: Idc48bd3eb82543a59715848088d341f311649fd6
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/test/ipmi_interface_mock.hpp b/test/ipmi_interface_mock.hpp
index f4ca0cf..bee3da4 100644
--- a/test/ipmi_interface_mock.hpp
+++ b/test/ipmi_interface_mock.hpp
@@ -1,5 +1,9 @@
 #pragma once
 
+#include "ipmi_interface.hpp"
+
+#include <gmock/gmock.h>
+
 class IpmiInterfaceMock : public IpmiInterface
 {
   public: