cfg80211: enable use of non-cleared DFS channels for DFS offload

Currently channel switch/start_ap to DFS channel cannot be done to
non-CAC-cleared channel even if DFS offload if enabled.
Make non-cleared DFS channels available if DFS offload is enabled.
CAC will be started by HW after channel change, start_ap call, etc.

Signed-off-by: Dmitry Lebed <dlebed@quantenna.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Change-Id: I381b973e7622195b5b88fe9e9f864a4d078ae425
Git-commit: 2c390e44e46675da0e7bba5c3b921a091a60ec2c
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next.git


CRs-fixed: 2265562
Signed-off-by: Peng Xu <pxu@codeaurora.org>