s390x/css: remove unused error handling branch

The case in question actually never happens. Let us get rid of the dead
code.
Signed-off-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Message-Id: <20170908152446.14606-4-pasic@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cohuck@redhat.com>

hw/s390x/css.c

@@ -980,13 +980,6 @@ static void sch_handle_start_func_virtual(SubchDev *sch)
                     SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
             s->cpa = sch->channel_prog + 8;
             break;
-        case -EBUSY:
-            /* subchannel busy, generate deferred cc 1 */
-            s->flags &= ~SCSW_FLAGS_MASK_CC;
-            s->flags |= (1 << 8);
-            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
-            s->ctrl |= SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
-            break;
         case -EINPROGRESS:
             /* channel program has been suspended */
             s->ctrl &= ~SCSW_ACTL_START_PEND;