9p: update documentation

quick pass to update the documentation to include instructions for
the new cache=mmap mode as well as clean up some out-of-date bits.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

Documentation/filesystems/9p.txt

@@ -69,10 +69,14 @@ OPTIONS
   		offering several exported file systems.
 
   cache=mode	specifies a caching policy.  By default, no caches are used.
+                        none = default no cache policy, metadata and data
+                                alike are synchronous.
 			loose = no attempts are made at consistency,
                                 intended for exclusive, read-only mounts
-			fscache = use FS-Cache for a persistent, read-only
+                        fscache = use FS-Cache for a persistent, read-only
 				cache backend.
+                        mmap = minimal cache that is only used for read-write
+                                mmap.  Northing else is cached, like cache=none
 
   debug=n	specifies debug level.  The debug level is a bitmask.
 			0x01  = display verbose error messages
@@ -147,8 +151,7 @@ on sourceforge (http://sourceforge.net/projects/v9fs).
 News and other information is maintained on a Wiki.
 (http://sf.net/apps/mediawiki/v9fs/index.php).
 
-Bug reports may be issued through the kernel.org bugzilla 
-(http://bugzilla.kernel.org)
+Bug reports are best issued via the mailing list.
 
 For more information on the Plan 9 Operating System check out
 http://plan9.bell-labs.com/plan9
@@ -156,11 +159,3 @@ http://plan9.bell-labs.com/plan9
 For information on Plan 9 from User Space (Plan 9 applications and libraries
 ported to Linux/BSD/OSX/etc) check out http://swtch.com/plan9
 
-
-STATUS
-======
-
-The 2.6 kernel support is working on PPC and x86.
-
-PLEASE USE THE KERNEL BUGZILLA TO REPORT PROBLEMS. (http://bugzilla.kernel.org)
-