[SCSI] pm80xx: no need for tag allocation when issuing the command of unregistering device

In function pm8001_dev_gone_notify we consume a tag from bitmap resource and
later don't free that tag resource, so the tag resource will never be
freed. In the function we don't need to use any tag to issue command for
unregistering the device .

Signed-off-by: XinHong Zhu <zxh3737@163.com>
Acked-by: Lindar Liu <lindar_liu@usish.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>