s390/qdio: fix output of DSCI value in debug file

The DSCI is a 1-byte field, placed at the start of an u32. So when
printing it to a queue's debug state, limit the output to the part
that's actually occupied by the DSCI.
When the DSCI is set this gives us the expected output of '1', rather
than the current (obscure) value of '16777216'.

Suggested-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>