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>

Having both IO-mapping.txt and io-mapping.txt in Documentation/
was confusing and/or bothersome to some people, so rename
IO-mapping.txt to bus-virt-phys-mapping.txt.  Also update
Documentation/00-INDEX for both of these files.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kees Bakker <kees.bakker@xs4all.nl>
Cc: Keith Packard <keithp@keithp.com>