[PATCH] Add AFS_SUPER_MAGIC to magic.h

Jeffrey Altman, one of the gatekeepers of OpenAFS (the open source project
which inherited the Transarc/IBM AFS codebase) has requested that the magic
number 0x5346414F (little endian 'OAFS') be allocated for the f_type field
of the fsinfo structure on Linux:

  https://lists.openafs.org/pipermail/openafs-info/2006-December/024829.html

Add it to include/linux/magic.h, mostly as a way of publishing this number
and ensuring that no other filesystem accidentally uses it.

Cc: Jeffrey Altman <jaltman@secure-endpoints.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>