[SCSI] remove dma_mask hacks

pci_alloc_consistent is under 4G by default.  Also simplify the
definition of bus_dmamap_t.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.h b/drivers/scsi/aic7xxx/aic7xxx_osm.h
index 752022e..9cfb46b 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.h
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.h
@@ -174,11 +174,7 @@
 };
 typedef struct ahc_linux_dma_tag* bus_dma_tag_t;
 
-struct ahc_linux_dmamap
-{
-	dma_addr_t	bus_addr;
-};
-typedef struct ahc_linux_dmamap* bus_dmamap_t;
+typedef dma_addr_t bus_dmamap_t;
 
 typedef int bus_dma_filter_t(void*, dma_addr_t);
 typedef void bus_dmamap_callback_t(void *, bus_dma_segment_t *, int, int);
@@ -479,7 +475,6 @@
 	uint32_t		 irq;		/* IRQ for this adapter */
 	uint32_t		 bios_address;
 	uint32_t		 mem_busaddr;	/* Mem Base Addr */
-	uint64_t		 hw_dma_mask;
 	ahc_linux_softc_flags	 flags;
 };