docbook: change iomap source filename in deviceiobook

From: Randy Dunlap <[email protected]>

Fix warning since kernel-doc comments were moved to another source file.

Warning(lib/iomap.c): no structured comments found

---
 Documentation/DocBook/deviceiobook.tmpl |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -317,7 +317,7 @@ CPU B:  spin_unlock_irqrestore(&dev_
   <chapter id="pubfunctions">
      <title>Public Functions Provided</title>
 !Iarch/x86/include/asm/io.h
-!Elib/iomap.c
+!Elib/pci_iomap.c
   </chapter>
 
 </book>