s390x/css: fix ilen in IO instruction handlers

When initiating a program check interruption by calling program_interrupt
the instruction length (ilen) of the current instruction is supplied as
the third parameter.

On s390x all the IO instructions are of instruction format S and their
ilen is 4.  The calls to program_interrupt (introduced by commits
7b18aad543 ("s390: Add channel I/O instructions.", 2013-01-24) and
61bf0dcb2e ("s390x/ioinst: Add missing alignment checks for IO
instructions", 2013-06-21)) however use ilen == 2.

This is probably due to a confusion between ilen which specifies the
instruction length in bytes and ILC which does the same but in halfwords.
If kvm_enabled() this does not actually matter, because the ilen
parameter of program_interrupt is effectively unused.

Let's provide the correct ilen to program_interrupt.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Fixes:  7b18aad543 ("s390: Add channel I/O instructions.")
Fixes: 61bf0dcb2e ("s390x/ioinst: Add missing alignment checks for IO instructions")
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20170724143452.55534-1-pasic@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
