scsi: bfa: release allocated memory in case of error

In bfad_im_get_stats if bfa_port_get_stats fails, allocated memory needs to
be released.

Link: https://lore.kernel.org/r/20190910234417.22151-1-navid.emamdoost@gmail.com
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
