Hi, as far as I'm concerned the only way to activate the gyroscope is updating your device to Android 6.0 In fact, I did this to play Pokémon GO too.Anyway you can enjoy the game without gyroscope, but if you are still interested you can see some links that I have just posted a couple of minutes ago in this same thread, it's not too hard to update your Huawei P8 Lite.
