net/mlx5: E-switch, Fix setting of reserved fields on MODIFY_SCHEDULING_ELEMENT

According to HW spec element_type, element_attributes and parent_element_id fields
should be reserved (0x0) when calling MODIFY_SCHEDULING_ELEMENT command.

This patch remove initialization of these fields when calling the command.

Fixes: bd77bf1c ("net/mlx5: Add SRIOV VF max rate configuration support")
Signed-off-by: Maor Dickman <maord@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>