wil6210: support Scheduled scan

Add support for sched_scan_start/stop by sending PNO commands to FW.
Driver reports max_sched_scan_reqs and invokes
cfg80211_sched_scan_results upon receiving WMI_SCHED_SCAN_RESULT_EVENTID
from FW.

Change-Id: Ie1e2bd405bf214d9618a61739412ee70b96b7602
Signed-off-by: Dedy Lansky <qca_dlansky@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Git-commit: a5dc688392737bbab3699d63f26e853a40c52d2d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git


[merez@codeaurora.org: fixes due to cfg80211 api changes]
Signed-off-by: Maya Erez <merez@codeaurora.org>