Replace ASC_VADDR_TO_U32 and ASC_U32_TO_VADDR with an auto-expanding
array that maps pointers to 32-bit IDs and back.  One of the uses of
ASC_VADDR_TO_U32 was in error; it should have been using ADV_VADDR_TO_U32.

Also replace the use of virt_to_bus when setting the sense_address with
a call to dma_map_single() followed by dma_cache_sync.  This part cribbed
from the 53c700 driver.
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>