[SCSI] zfcp: Fix cast warning

Fix leftover from last typecast patch:

drivers/s390/scsi/zfcp_aux.c: In function ‘zfcp_port_enqueue’:
drivers/s390/scsi/zfcp_aux.c:629: warning: format ‘%016llx’ expects
type ‘long long unsigned int’, but argument 3 has type ‘u64’

Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>