mlx4_core: Fix unused variable warning

Fix

   drivers/net/mlx4/profile.c:55: warning: 'res_name' defined but not used

by making mlx4_dbg() always use all of its parameters, regardless of
whether CONFIG_MLX4_DEBUG is set or not.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/net/mlx4/mlx4.h

@@ -87,19 +87,16 @@ enum {
 
 #ifdef CONFIG_MLX4_DEBUG
 extern int mlx4_debug_level;
+#else /* CONFIG_MLX4_DEBUG */
+#define mlx4_debug_level	(0)
+#endif /* CONFIG_MLX4_DEBUG */
 
 #define mlx4_dbg(mdev, format, arg...)					\
 	do {								\
 		if (mlx4_debug_level)					\
 			dev_printk(KERN_DEBUG, &mdev->pdev->dev, format, ## arg); \
 	} while (0)
 
-#else /* CONFIG_MLX4_DEBUG */
-
-#define mlx4_dbg(mdev, format, arg...) do { (void) mdev; } while (0)
-
-#endif /* CONFIG_MLX4_DEBUG */
-
 #define mlx4_err(mdev, format, arg...) \
 	dev_err(&mdev->pdev->dev, format, ## arg)
 #define mlx4_info(mdev, format, arg...) \