scsi: sr: Simplify the sr_open() function

Simplify the sr_open() by removing the goto label as the function only
returns one error code.

Signed-off-by: Enze Li <lienze@kylinos.cn>
Link: https://lore.kernel.org/r/20230327030237.3407253-1-lienze@kylinos.cn
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>