I can confirm that I see the same on Dell Lattitude 7370, Ubuntu 16.04, kernel 4.4.0-38-generic.
$ xinput list ⎡ Virtual core pointer id=2 [master pointer (3)] ⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)] ⎜ ↳ ELAN Touchscreen id=10 [slave pointer (2)] ⎜ ↳ ImPS/2 Generic Wheel Mouse id=13 [slave pointer (2)] ⎣ Virtual core keyboard id=3 [master keyboard (2)] ↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)] ↳ Power Button id=6 [slave keyboard (3)] ↳ Video Bus id=7 [slave keyboard (3)] ↳ Power Button id=8 [slave keyboard (3)] ↳ Sleep Button id=9 [slave keyboard (3)] ↳ Integrated_Webcam_HD id=11 [slave keyboard (3)] ↳ AT Translated Set 2 keyboard id=12 [slave keyboard (3)] ↳ Dell WMI hotkeys id=14 [slave keyboard (3)] ↳ DELL Wireless hotkeys id=15 [slave keyboard (3)]
From dmesg: [ 4.806149] input: ImPS/2 Generic Wheel Mouse as /devices/platform/i8042/serio1/input/input6
I can confirm that I see the same on Dell Lattitude 7370, Ubuntu 16.04, kernel 4.4.0-38-generic.
$ xinput list Webcam_ HD id=11 [slave keyboard (3)]
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ ELAN Touchscreen id=10 [slave pointer (2)]
⎜ ↳ ImPS/2 Generic Wheel Mouse id=13 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Video Bus id=7 [slave keyboard (3)]
↳ Power Button id=8 [slave keyboard (3)]
↳ Sleep Button id=9 [slave keyboard (3)]
↳ Integrated_
↳ AT Translated Set 2 keyboard id=12 [slave keyboard (3)]
↳ Dell WMI hotkeys id=14 [slave keyboard (3)]
↳ DELL Wireless hotkeys id=15 [slave keyboard (3)]
From dmesg: platform/ i8042/serio1/ input/input6
[ 4.806149] input: ImPS/2 Generic Wheel Mouse as /devices/