net/mlx4_core: Remove zeroed out of explicit QUERY_FUNC_CAP fields

All mailboxes are already zeroed by commit:
571b8b92 net/mlx4_core: Initialize all mailbox buffers to zero before use
Remove explicit zero set for force mac and force vlan fields in
mlx4_QUERY_FUNC_CAP_wrapper

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>