net/mlx5: use mask for meter register setting

net/mlx5: use mask for meter register setting

ASO (Advanced Steering Operation) meter feature may require
to locate the flow context tag action after the ASO action.
When color register is shared by meter_id/flow_id, it's like:
Bits[0-7] A meter color value set by the HW.
Bits[8-31] A flow id and meter id set by SW.

Currently the tag action for meter writes all the bits
of the meter register, so it will potentially overwrite
meter color when ASO meter action is before the tag action.

Set only 24-MSB-bits of meter register in the meter tag action.

Signed-off-by: Shun Hao <shunh@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>