ipr: Inhibit underlength data check for AFDASD in raw mode.

Disable underlength error verification based on count of bytes actually
transferred for AF DASD devices when SIS pipe mode is enabled.

This avoids unexpected underlength errors when issuing some commands in
raw mode.

Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>