Add a new QCA vendor attribute
QCA_WLAN_VENDOR_ATTR_ACS_LAST_SCAN_AGEOUT_TIME to
QCA_NL80211_VENDOR_SUBCMD_DO_ACS and opportunistically optimize time
taken for ACS scan. Avoid scanning the channels which were scanned
within last QCA_WLAN_VENDOR_ATTR_ACS_LAST_SCAN_AGEOUT_TIME milliseconds
and use scan results from scan results cache for ACS scoring. For other
channels, perform ACS scan and use the received scan results.
Change-Id: I5f57002566870fea7444358711205392e5e84053
CRs-Fixed: 3226134
29073d2cf5