net/mlx5e: Make stats group fill_stats callbacks consistent with the API

The fill_strings() callbacks were changed to accept a **data pointer,
and not rely on propagating the index value.
Make a similar change to fill_stats() callbacks to keep the API
consistent.

Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240402133043.56322-5-tariqt@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>