[SCSI] zfcp: Move SCSI host and transport templates out of struct zfcp_data

The SCSI host and transport templates are the only members left in the
global zfcp_data struct. Move them out of zfcp_data  and remove the
now unused zfcp_data struct. Also update the names of the register and
unregister functions to use the zfcp_scsi prefix.

Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>