ceph: add newline to end of debug message format

Some of dout format do not include newline in the end,
fix for the files which are in fs/ceph and net/ceph directories,
and changing printk to dout for printing debug info in super.c

Signed-off-by: Chengguang Xu <cgxu519@icloud.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>