linux-phytec-fsl

cfg80211: move function checking range fit to util.c

It is needed for another cfg80211 helper that will be out of reg.c so
move it to common util.c file and make it non-static.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>