mlx4_core: Directly expose fields of DMFS HW rule control segment

Some of struct mlx4_net_trans_rule_hw_ctrl fields were packed into u32
and accessed through bit field operations.  Expose and access them
directly as u8 or u16.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>