scsi: target: Remove redundant assignment to variable 'ret'

The variable ret has been initialized with a value '0'. The assignment in
switch-case is redundant. Remove it.

Link: https://lore.kernel.org/r/20200914023207.113792-1-jingxiangfeng@huawei.com


Reviewed-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>