linuxkpi: Introduce module_param() of type bint

In Linux, this limits the accepted value to -1, 0 and 1.
In FreeBSD, this remains a signed integer with no specific constraints.

This change is a requirement to update our DRM drivers to Linux 5.12.

Differential Revision: https://reviews.freebsd.org/D37364

(cherry picked from commit e101c1c2c9ba18b1dd0eb2000106fafc915babdc)