net/mlx5: fix uninit value use

Avoid use of uninitialized state variable.

In case of mlx5e_tx_reporter_build_diagnose_output_sq_common() it's better
to still collect other data than bail out entirely.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/netdev/8bd30131-c9f2-4075-a575-7fa2793a1760@moroto.mountain
Fixes: d17f98bf

 ("net/mlx5: devlink health: use retained error fmsg API")
Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Link: https://lore.kernel.org/r/20231025145050.36114-1-przemyslaw.kitszel@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>