s390x/tcg: a CPU cannot switch state due to an interrupt

Going to OPERATING here looks wrong. A CPU should even never be
!OPERATING at this point. Unhalting will already be done in
cpu_handle_halt() if there is work, so we can drop this statement
completely.
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20170928203708.9376-8-david@redhat.com>
Signed-off-by: NCornelia Huck <cohuck@redhat.com>

target/s390x/excp_helper.c

@@ -438,7 +438,6 @@ void s390_cpu_do_interrupt(CPUState *cs)
     qemu_log_mask(CPU_LOG_INT, "%s: %d at pc=%" PRIx64 "\n",
                   __func__, cs->exception_index, env->psw.addr);
 
-    s390_cpu_set_state(CPU_STATE_OPERATING, cpu);
     /* handle machine checks */
     if (cs->exception_index == -1 && s390_cpu_has_mcck_int(cpu)) {
         cs->exception_index = EXCP_MCHK;