quirks: tighten the match for the Graviton N15i touchpad
Other systems use the same touchpad but without physical buttons (e.g. SpeedMind M-BOOK) and obviously the various systems using the 5288 touchpad, see commit d1f274c7.
Let's tighten this quirk to just the Graviton only.
Closes #970 (closed)
Fixes 8163b552be23ef3f4082775649bb12a3f6162df6
Related !957 (merged)