[IWLWIFI]: remove per-file CFLAGS for IWL define

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-rs.c b/drivers/net/wireless/iwlwifi/iwl-4965-rs.c
index 7b74481..bc5e67b 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-rs.c
@@ -39,6 +39,8 @@
 #include <net/mac80211.h>
 #include <linux/wireless.h>
 
+#define IWL 4965
+
 #include "../net/mac80211/ieee80211_rate.h"
 
 #include "iwlwifi.h"