LinuxKPI: implement devm_kmemdup_array()

Implement devm_kmemdup_array() using devm_kmemdup() in order to
prepare for Linux v7.0 based drivers.

Sponsored by: The FreeBSD Foundation
Reviewed by: dumbbell
Differential Revision: https://reviews.freebsd.org/D56396

(cherry picked from commit f1834d03af617a93993056bb902082452673f89f)