mlx4_core: remove buggy sched_queue masking

Fixes a bug introduced by commit fe9a2603, where the priority bits
in the schedule queue field were masked out.

Signed-off-by: Amir Vadai <amirv@mellanox.co.il>
Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>