net/mlx5e: Generalize packet merge error message

Update the old error message for LRO state modify with the new
general name.

Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Khalid Manaa <khalidm@nvidia.com>
Reviewed-by: Gal Pressman <gal@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>