LinuxKPI: Add cpu_latency_qos_request_active stub to linux/pm_qos.h

Required by: drm-kmod 5.10

MFC after: 1 week
Reviewers: hselasky, manu
Differential Revision: https://reviews.freebsd.org/D35049

(cherry picked from commit 6bcd13222215da58f17a54db1592afc36df47f83)