jffs2: move jffs2_write_super to super.c

jffs2_write_super is only called from super.c and doesn't use any
functionality from fs.c.  So move it over to super.c and make it
static there.

[should go in through the vfs tree as it is a requirement for the
 next patch]

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Al Viro <[email protected]>
3 files changed