mlx5_core: Copy DIF fields only when input and output space values match

Some DIF implementations (SCSI initiator/target) may want to use different
input/output values for application tag and/or reference tag. So in
case memory/wire domain values don't match HW must not copy them.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>