nl80211: use __cfg80211_rdev_from_attrs for testmode
nl80211: use __cfg80211_rdev_from_attrs for testmode

To fix the testmode cross-namespace access problem,
use __cfg80211_rdev_from_attrs() to get the device
instead of open-coding similar functionality.

Signed-off-by: Johannes Berg <bff32994ff0f8d048f262a8388145a71b6071bfe@intel.com>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs