Let's initialize the structs at the beginning to ease reading and also
zeroing all other fields. This also makes the compiler stop
complaining about sense_id_ccw.flags being ored into when it's not
initialized.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20200624075226.92728-2-frankja@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>