scsi: lpfc: Add missing misc_deregister() for lpfc_init()

lpfc_init() misses a call misc_deregister() in an error path. Add a label
'unregister' to fix it.

Link: https://lore.kernel.org/r/20200731065639.190646-1-jingxiangfeng@huawei.com


Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>