vdpa/mlx5: Remove redundant header file inclusion

linux/if_vlan.h is not required.
Remove it.
Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20210823052123.14909-2-elic@nvidia.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/mlx5/core/mlx5_vdpa.h

@@ -5,7 +5,6 @@
 #define __MLX5_VDPA_H__
 
 #include <linux/etherdevice.h>
-#include <linux/if_vlan.h>
 #include <linux/vdpa.h>
 #include <linux/mlx5/driver.h>