bthidd(8): Generate button release event after virtual T-axis button press

Apply PR/213957 (r308165, Make sure the virtual T-axis buttons generate button
release event(s) for continuous tilting) to bluetooth mouse support.

Reviewed by: emax, gonzo
Approved by: gonzo (mentor)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D12672