net/mlx5e: Fix return value from timeout recover function

Fix timeout recover function to return a meaningful return value.
When an interrupt was not sent by the FW, return IO error instead of
'true'.

Fixes: c7981bea ("net/mlx5e: Fix return status of TX reporter timeout recover")
Signed-off-by: Aya Levin <ayal@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>