net/mlx5e: Use extack in get coalesce callback

In case of errors in get coalesce, reflect it through extack instead of
a dmesg print.

Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20240808055927.2059700-8-tariqt@nvidia.com


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