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>

arch/arm/include/asm/io.h

@@ -238,7 +238,7 @@ extern void _memset_io(volatile void __iomem *, int, size_t);
  * ioremap and friends.
  *
  * ioremap takes a PCI memory address, as specified in
- * Documentation/IO-mapping.txt.
+ * Documentation/io-mapping.txt.
  *
  */
 #ifndef __arch_ioremap