wlan: Fix RX thread stuck in while loop

Currently during roaming for LFR make before break feature under
stress testing RX thread is stuck in while loop resulting in host
RX low resource and firmware watch dog bite. In this change refactor
the code to check for null termination of the received frames rather
than checking for the local variable pointer assigned to the input
received frames.

Change-Id: I47b40566d52134b58304541c708cd87263fabfc6
CRs-Fixed: 2009414
diff --git a/CORE/TL/src/wlan_qct_tl.c b/CORE/TL/src/wlan_qct_tl.c
index 3be2835..4e7ad14 100755
--- a/CORE/TL/src/wlan_qct_tl.c
+++ b/CORE/TL/src/wlan_qct_tl.c
@@ -6227,7 +6227,7 @@
    ---------------------------------------------------------------------*/
   vosTempBuff = vosDataBuff;
 
-  while ( NULL != vosTempBuff )
+  while (NULL != vosDataBuff)
   {
     broadcast = VOS_FALSE;
     selfBcastLoopback = VOS_FALSE;