scsi: sg: Fix sysctl sg-big-buff register during sg_init()

scsi: sg: Fix sysctl sg-big-buff register during sg_init()

Commit 26d1c80fd61e ("scsi/sg: move sg-big-buff sysctl to scsi/sg.c") made
a mistake. sysctl sg-big-buff was not created because the call to
register_sg_sysctls() was placed on the wrong code path.

Fixes: 26d1c80fd61e ("scsi/sg: move sg-big-buff sysctl to scsi/sg.c")
Signed-off-by: Yang Erkun <yangerkun@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260127062044.3034148-2-yangerkun@huawei.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>