qcacld-3.0: Change to address memory leak

qcacld-2.0 to qcacld-3.0 propagation

As per the current implementation during join timer start failure scenario,
pMlmJoinReq assigned to NULL with out freeing the memory resulting in
memory leak.

change made to release the memory in failure scenario.

Change-Id: I3f37f45129baec76671caff09790bfb70bf01208
CRs-Fixed: 930553

core/mac/src/pe/lim/lim_process_mlm_rsp_messages.c

@@ -3551,7 +3551,6 @@ static void lim_process_switch_channel_join_req(
 		MTRACE(mac_trace(mac_ctx, TRACE_CODE_MLM_STATE,
 			 session_entry->peSessionId,
 			 mac_ctx->lim.gLimMlmState));
-		session_entry->pLimMlmJoinReq = NULL;
 		goto error;
 	}
 	/* include additional IE if there is */