Return the correct error code when the SCCB buffer is too small to
contain all of the output, for the Read SCP Information and
Read CPU Information commands.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
Message-Id: <1569591203-15258-5-git-send-email-imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>