KVM: s390: Do not set CC3 for EQBS and SQBS

The EQBS and SQBS instructions do not set CC3 for invalid channels, but
should throw an operation exception instead when not available. Thus they
should not be handled by the handle_io_inst() wrapper but drop to userspace
instead (which will then inject the operation exception).

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>