[SCSI] ipr: possible irq lock inversion dependency detected

When enable lockdep, seeing "possible irq lock inversion dependency detected"
error. This patch fixes the issue.

Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>