LinuxKPI: lockdep add lockdep_assert_not_held()

Add lockdep_assert_not_held() asserting LA_UNLOCKED as needed by a
driver.

Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D34232

(cherry picked from commit 064c110f4b551cbf3f2ef6f567736005c2d7007a)