LinuxKPI: 802.11 fix locking in lkpi_stop_hw_scan()

In lkpi_stop_hw_scan() we have to unlock around cancelling the
hardware scan and an msleep to wait for the confirmation that the
scan ended. Otherwise we are sleeping with the non-sleepable
net80211 com lock held. At the same time we need to hold the lhw
lock for the msleep().
This lock change got lost in the refactoring of lkpi_iv_newstate().

Reported by: ambrisko, delphij
PR: 261075
Sponsored by: The FreeBSD Foundation

(cherry picked from commit bec766282f242aab3a4bfba402ea74cb0ccf96fb)