wlan: Add support for PER based roaming #2

In congested environments, it could be possible that in station
mode client gets good RSSI from AP however it's not able to
transfer data at good rates. DUT should roam to a better AP if
available, if it faces congestion in home channel.

Following changes are added for this functionality:
1. Add changes to monitor Rx and Tx rates to trigger roam scan
in case data rates are low below a preconfigured value.
2. Implement a new AP selection algorithm which will consider AP
capabilty, channel conditions and RSSI to select new bss.

Add required protocol changes for same.

Change-Id: I394c15b54ea95aa08f648f33383cb0a364278585
CRs-Fixed: 1031345
diff --git a/CORE/SME/inc/csrInternal.h b/CORE/SME/inc/csrInternal.h
index 9729f6e..daf16c9 100644
--- a/CORE/SME/inc/csrInternal.h
+++ b/CORE/SME/inc/csrInternal.h
@@ -623,6 +623,13 @@
 #ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
     tANI_U8      isRoamOffloadScanEnabled;
     tANI_BOOLEAN bFastRoamInConIniFeatureEnabled;
+    v_BOOL_t     isPERRoamEnabled;
+    v_BOOL_t     isPERRoamCCAEnabled;
+    tANI_U32     rateUpThreshold;
+    tANI_U32     rateDownThreshold;
+    tANI_U32     waitPeriodForNextPERScan;
+    tANI_U32     PERtimerThreshold;
+    tANI_U32     PERroamTriggerPercent;
 #endif
 #endif