Userspace can update the full scan period through the roam subcmd
QCA_WLAN_VENDOR_ROAMING_SUBCMD_CONTROL_SET and the attribute
QCA_ATTR_ROAM_CONTROL_FULL_SCAN_PERIOD. Send the same to firmware
as part of roam scan offload command
Change-Id: I7c1046763d693faa3340b655848d3306ef92e06c
CRs-Fixed: 2508775