Doc fix: ext2 can only have 32,000 subdirs, not 32,768

ext2.txt says that dirs can have 32,768 subdirs, but the actual value of
EXT2_LINK_MAX is 32000.

ext3 is the same, but the doc does not mention it.  One of ext4's features
is to "fix 32000 subdirectory limit".
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/ext2.txt

@@ -322,7 +322,7 @@ an upper limit on the block size imposed by the page size of the kernel,
 so 8kB blocks are only allowed on Alpha systems (and other architectures
 which support larger pages).
 
-There is an upper limit of 32768 subdirectories in a single directory.
+There is an upper limit of 32000 subdirectories in a single directory.
 
 There is a "soft" upper limit of about 10-15k files in a single directory
 with the current linear linked-list directory implementation.  This limit