[S390] qdio: remove superfluous log entries and WARN_ONs.

[S390] qdio: remove superfluous log entries and WARN_ONs.

* Don't write debug feature log entries for sl, slsb and sbal since these
  elements can be located from the qdio_q pointer which is also logged.
* Convert WARN_ON for wrong alignment of sbal to BUG_ON.
* Remove WARN_ON's for wrong alignment of q / qib / slib since these
  alignments should be guaranteed by kmem_cache_alloc alignment /
  struct aligned attribute / __get_free_page.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>