doc: fix broken references

There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.

Fix these broken references, sometimes by dropping the irrelevant text
they were part of.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/parisc/sba_iommu.c b/drivers/parisc/sba_iommu.c
index 57a6d19..a6f7621 100644
--- a/drivers/parisc/sba_iommu.c
+++ b/drivers/parisc/sba_iommu.c
@@ -668,7 +668,7 @@
  * @dev: instance of PCI owned by the driver that's asking
  * @mask:  number of address bits this PCI device can handle
  *
- * See Documentation/PCI/PCI-DMA-mapping.txt
+ * See Documentation/DMA-API-HOWTO.txt
  */
 static int sba_dma_supported( struct device *dev, u64 mask)
 {
@@ -680,7 +680,7 @@
 		return(0);
 	}
 
-	/* Documentation/PCI/PCI-DMA-mapping.txt tells drivers to try 64-bit
+	/* Documentation/DMA-API-HOWTO.txt tells drivers to try 64-bit
 	 * first, then fall back to 32-bit if that fails.
 	 * We are just "encouraging" 32-bit DMA masks here since we can
 	 * never allow IOMMU bypass unless we add special support for ZX1.
@@ -706,7 +706,7 @@
  * @size:  number of bytes to map in driver buffer.
  * @direction:  R/W or both.
  *
- * See Documentation/PCI/PCI-DMA-mapping.txt
+ * See Documentation/DMA-API-HOWTO.txt
  */
 static dma_addr_t
 sba_map_single(struct device *dev, void *addr, size_t size,
@@ -785,7 +785,7 @@
  * @size:  number of bytes mapped in driver buffer.
  * @direction:  R/W or both.
  *
- * See Documentation/PCI/PCI-DMA-mapping.txt
+ * See Documentation/DMA-API-HOWTO.txt
  */
 static void
 sba_unmap_single(struct device *dev, dma_addr_t iova, size_t size,
@@ -861,7 +861,7 @@
  * @size:  number of bytes mapped in driver buffer.
  * @dma_handle:  IOVA of new buffer.
  *
- * See Documentation/PCI/PCI-DMA-mapping.txt
+ * See Documentation/DMA-API-HOWTO.txt
  */
 static void *sba_alloc_consistent(struct device *hwdev, size_t size,
 					dma_addr_t *dma_handle, gfp_t gfp)
@@ -892,7 +892,7 @@
  * @vaddr:  virtual address IOVA of "consistent" buffer.
  * @dma_handler:  IO virtual address of "consistent" buffer.
  *
- * See Documentation/PCI/PCI-DMA-mapping.txt
+ * See Documentation/DMA-API-HOWTO.txt
  */
 static void
 sba_free_consistent(struct device *hwdev, size_t size, void *vaddr,
@@ -927,7 +927,7 @@
  * @nents:  number of entries in list
  * @direction:  R/W or both.
  *
- * See Documentation/PCI/PCI-DMA-mapping.txt
+ * See Documentation/DMA-API-HOWTO.txt
  */
 static int
 sba_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
@@ -1011,7 +1011,7 @@
  * @nents:  number of entries in list
  * @direction:  R/W or both.
  *
- * See Documentation/PCI/PCI-DMA-mapping.txt
+ * See Documentation/DMA-API-HOWTO.txt
  */
 static void 
 sba_unmap_sg(struct device *dev, struct scatterlist *sglist, int nents,