[SCSI] zfcp: Remove initial device data from zfcp_data

The information from the kernel parameter is only needed during init.
Keep the three pieces (busid, wwpn and lun) local to simplify the
global zfcp_data structures. While at it, also remove the unused
loglevel variable and give the module parameter variable a better
name.

Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Acked-by: Felix Beck <felix@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>