[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/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index cc405f4..44f983b 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -58,6 +58,8 @@
 
 #include <asm/div64.h>
 
+#define IWL 3945
+
 #include "iwlwifi.h"
 #include "iwl-3945.h"
 #include "iwl-helpers.h"