[SCSI] hptiop: fix RR312x in hosts with >12GB

As the limitation of RR312x's dma engine, the HBA can not access host memory
over 12GB.  This fixes

https://bugzilla.kernel.org/show_bug.cgi?id=14311

[alan: resurrected bug from 2009 and pushed upstream]
Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: HighPoint Linux Team <linux@highpoint-tech.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/hptiop.h

@@ -297,6 +297,7 @@ struct hptiop_adapter_ops {
 	int  (*iop_intr)(struct hptiop_hba *hba);
 	void (*post_msg)(struct hptiop_hba *hba, u32 msg);
 	void (*post_req)(struct hptiop_hba *hba, struct hptiop_request *_req);
+	int  hw_dma_bit_mask;
 };
 
 #define HPT_IOCTL_RESULT_OK         0