qcacld-3.0: Remove struct hdd_config::get_roam_chan_from_fw

The following patch added get_roam_chan_from_fw to struct hdd_config:
  qcacld-3.0: Add support to get roam scan channels from fw
  Change-Id I690aca6c3f1e3aa7ae1fe54aadc839ea19446079

However, that member isn't actually used, so remove it.

Change-Id: Icc490935c82396f5469be14812bb66dbb5299312
CRs-Fixed: 3424940

core/hdd/inc/wlan_hdd_cfg.h

@@ -194,7 +194,6 @@ struct hdd_config {
 	bool enable_sar_safety;
 	bool config_sar_safety_sleep_index;
 #endif
-	bool get_roam_chan_from_fw;
 	uint8_t nb_commands_interval;
 
 #ifdef FEATURE_CLUB_LL_STATS_AND_GET_STATION