fs: move exportfs since it is not a networking filesystem

Move the EXPORTFS kconfig symbol out of the NETWORK_FILESYSTEMS block
since it provides a library function that can be (and is) used by other
(non-network) filesystems.

This also eliminates a kconfig dependency warning:

warning: (XFS_FS && BLOCK || NFSD && NETWORK_FILESYSTEMS && INET && FILE_LOCKING && BKL) selects EXPORTFS which has unmet direct dependencies (NETWORK_FILESYSTEMS)
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: xfs-masters@oss.sgi.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/Kconfig

@@ -47,6 +47,9 @@ source "fs/nilfs2/Kconfig"
 
 endif # BLOCK
 
+config EXPORTFS
+	tristate
+
 config FILE_LOCKING
 	bool "Enable POSIX file locking API" if EMBEDDED
 	default y
@@ -222,9 +225,6 @@ config LOCKD_V4
 	depends on FILE_LOCKING
 	default y
 
-config EXPORTFS
-	tristate
-
 config NFS_ACL_SUPPORT
 	tristate
 	select FS_POSIX_ACL