Create libi2c_dev_mock.a to solve linker errors

The i2c::create() function is currently defined in
mocked_i2c_interface.hpp.  This causes linker errors if that header file
is included by multiple .cpp files in the same test executable.

Moved i2c::create() to mocked_i2c_interface.cpp so that it is only
defined once.  Created the static library libi2c_dev_mock.a that
contains mocked_i2c_interface.o.

Test executables that need the mock version of i2c::create() should link
with libi2c_dev_mock.a.

Normal executables that need the real version of i2c::create() should
link with libi2c_dev.a as before.  This has not changed.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: Ic00203c5429c1a2162327905ba547602258c6b0d
diff --git a/tools/power-utils/test/test_updater.cpp b/tools/power-utils/test/test_updater.cpp
index c51c233..6ad3f73 100644
--- a/tools/power-utils/test/test_updater.cpp
+++ b/tools/power-utils/test/test_updater.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 #include "../updater.hpp"
-#include "test/mocked_i2c_interface.hpp"
+#include "mocked_i2c_interface.hpp"
 
 #include <filesystem>