qcacmn: Adjust the bin5 rssi threshold in radar filters

Radar bandwidth detection at certain frquencies is reported to
be lower than the acceptable threshold.  This is due to the low
rssi reported in the phyerrors.

Fix the issue by adjusting the rssi threshold accordingly.

Change-Id: Ia1598342e33b1217a1fb163878b2ac42661b33af
CRs-Fixed: 2184681

umac/dfs/core/src/filtering/dfs_radar.c

@@ -96,7 +96,7 @@ struct dfs_pulse dfs_mkk4_radars[] = {
  *                                           chipsets.
  */
 struct dfs_bin5pulse dfs_fcc_bin5pulses[] = {
-	{5, 28, 105, 12, 22, 5},
+	{6, 28, 105, 12, 18, 5},
 };
 
 /**