Documentation: rename PCI-DMA-mapping.txt to DMA-API-HOWTO.txt

Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/DMA-API.txt

@@ -5,7 +5,7 @@
 
 This document describes the DMA API.  For a more gentle introduction
 of the API (and actual examples) see
-Documentation/PCI/PCI-DMA-mapping.txt.
+Documentation/DMA-API-HOWTO.txt.
 
 This API is split into two pieces.  Part I describes the API.  Part II
 describes the extensions to the API for supporting non-consistent