[S390] cio: Remove cio_msg kernel parameter.

The only sporadically used CIO_DEBUG messages are replaced by ordinary
CIO_MSG_EVENT messages. The CIO_MSG_EVENT messages debug levels are
consolidated.

Signed-off-by: Michael Ernst <mernst@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>