wlan: Use csrIsConcurrentInfraConnected() API.

Use csrIsConcurrentInfraConnected() instead of
vos_concurrent_session_running()

Change-Id: I65bed9c24c69e8dea081b38305037554a2122b0a
CR-Fixed: 408819, 408912
diff --git a/CORE/SME/src/csr/csrApiRoam.c b/CORE/SME/src/csr/csrApiRoam.c
index a1fca78..791474a 100644
--- a/CORE/SME/src/csr/csrApiRoam.c
+++ b/CORE/SME/src/csr/csrApiRoam.c
@@ -4363,7 +4363,8 @@
 //Returns whether "Legacy Fast Roaming" is currently enabled...or not
 tANI_BOOLEAN csrRoamIsFastRoamEnabled(tpAniSirGlobal pMac)
 {
-    return pMac->roam.configParam.isFastRoamIniFeatureEnabled;
+    return (pMac->roam.configParam.isFastRoamIniFeatureEnabled &&
+            (!csrIsConcurrentInfraConnected(pMac)));
 }
 #endif