fs/ceph/debugfs.c: replace seq_printf by seq_puts

Replace seq_printf where possible.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Sage Weil <sage@inktank.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>