Force C++ linking of the gpu_utils

Force C++ linking of the gpu_utils

As the gpu_utils module contains some exception handling (in memtestG80)
we need to force C++ linking of this library. This allows us to remove
the --add-needed linker flag which was not the appropriate solution for
the otherwise failing linking due to the following ld error:
undefined reference to symbol '__cxa_throw@@CXXABI_1.3'

Change-Id: I333b5506abdee2f790781a6524c475c56db6eac0