When allocating log_to_span fails, kfree(instance->ctrl_context) is called
twice. Remove redundant call.

Link: https://lore.kernel.org/r/1659424729-46502-1-git-send-email-kanie@linux.alibaba.comAcked-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>