net/mlx4_core: Fix several coding style errors

Fix 3 checkpatch errors within mlx4/main.c:
- Unnecessary mlx4_debug_level global variable initialization to 0.
- Prohibited space before comma.
- Whitespaces instead of tab.

Signed-off-by: Erez Alfasi <ereza@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/main.c

@@ -63,7 +63,7 @@ struct workqueue_struct *mlx4_wq;
 
 #ifdef CONFIG_MLX4_DEBUG
 
-int mlx4_debug_level = 0;
+int mlx4_debug_level; /* 0 by default */
 module_param_named(debug_level, mlx4_debug_level, int, 0644);
 MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0");