scsi: sd_zbc: Place function name into header

scsi: sd_zbc: Place function name into header

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/sd_zbc.c:137: warning: wrong kernel-doc identifier on line:

Link: https://lore.kernel.org/r/20210317091230.2912389-5-lee.jones@linaro.org
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Le Moal <damien.lemoal@hgst.com>
Cc: Shaun Tancheff <shaun.tancheff@seagate.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>