autofs4: keep symlink body in inode->i_private

gets rid of all ->free()/->u.symlink machinery in autofs; we simply
keep symlink bodies in inode->i_private and free them in ->evict_inode().

Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --cc fs/autofs4/autofs_i.h
Simple merge

diff --cc fs/autofs4/inode.c
Simple merge

diff --cc fs/autofs4/root.c
Simple merge

diff --cc fs/autofs4/symlink.c
Simple merge