[SCSI] arcmsr: upper 32 of dma address lost

The original code always set the upper 32 bits to zero because it was
doing a shift of the wrong variable.

Change-Id: I2cad5247475f4454bcaa84d2bef0bbb3dc2a9fe2
Fixes: 1a4f550a09f8 ('[SCSI] arcmsr: 1.20.00.15: add SATA RAID plus other fixes')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>