net/mlx5: Skip inline mode check after mlx5_eswitch_enable_locked() failure

Commit bffaa916 ("net/mlx5: E-Switch, Add control for inline mode")
added inline mode checking to esw_offloads_start() with a warning
printed out in case there is a problem. Tne inline mode checking was
done even after mlx5_eswitch_enable_locked() call failed, which is
pointless.

Later on, commit 8c98ee77 ("net/mlx5e: E-Switch, Add extack messages
to devlink callbacks") converted the error/warning prints to extack
setting, which caused that the inline mode check error to overwrite
possible previous extack message when mlx5_eswitch_enable_locked()
failed. User then gets confusing error message.

Fix this by skipping check of inline mode after
mlx5_eswitch_enable_locked() call failed.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>