[SCSI] zfcp: fix logging during device reset

Avoid access to old fsf_requests if device reset is logged.

Signed-off-by: Maxim Shchetynin <maxim@de.ibm.com>
Signed-off-by: Andreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>