scsi: libsas: fix error when getting phy events

scsi: libsas: fix error when getting phy events

The intend purpose here was to goto out if smp_execute_task() returned
error. Obviously something got screwed up. We will never get these link
error statistics below:

~:/sys/class/sas_phy/phy-1:0:12 # cat invalid_dword_count
0
~:/sys/class/sas_phy/phy-1:0:12 # cat running_disparity_error_count
0
~:/sys/class/sas_phy/phy-1:0:12 # cat loss_of_dword_sync_count
0
~:/sys/class/sas_phy/phy-1:0:12 # cat phy_reset_problem_count
0

Obviously we should goto error handler if smp_execute_task() returns
non-zero.

Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver")
Signed-off-by: Jason Yan <yanaijie@huawei.com>
CC: John Garry <john.garry@huawei.com>
CC: chenqilin <chenqilin2@huawei.com>
CC: chenxiang <chenxiang66@hisilicon.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>