ieee1394: revert "sbp2: enforce 32bit DMA mapping"

Revert commit 0555659d from 2.6.22-rc1.
The dma_set_mask call somehow failed on a PowerMac G5, PPC64:
http://lkml.org/lkml/2007/8/1/344

Should there ever occur a DMA mapping beyond the physical DMA range, a
proper SBP-2 firmware will report transport errors.  So let's leave it
at that.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Olaf Hering <olh@suse.de>

drivers/ieee1394/sbp2.c

@@ -773,11 +773,6 @@ static struct sbp2_lu *sbp2_alloc_device(struct unit_directory *ud)
 			SBP2_ERR("failed to register lower 4GB address range");
 			goto failed_alloc;
 		}
-#else
-		if (dma_set_mask(hi->host->device.parent, DMA_32BIT_MASK)) {
-			SBP2_ERR("failed to set 4GB DMA mask");
-			goto failed_alloc;
-		}
 #endif
 	}