refactor(utils): Cleanup unused code

Author: gfieni

src/powerapi/utils/__init__.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2021, INRIA
+# Copyright (c) 2021, Inria
 # Copyright (c) 2021, University of Lille
 # All rights reserved.
 #
@@ -26,5 +26,3 @@
 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-from .utils import timestamp_to_datetime