VFS: Unexport do_kern_mount() and clean up simple_pin_fs()

Replace all module uses with the new vfs_kern_mount() interface, and fix up
simple_pin_fs().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 53c56e7..93a7821 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -48,7 +48,7 @@
 
 static void afs_destroy_inode(struct inode *inode);
 
-static struct file_system_type afs_fs_type = {
+struct file_system_type afs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "afs",
 	.get_sb		= afs_get_sb,