pseries: Correct panic behaviour for pseries machine type

The pseries machine type doesn't usually use the 'pvpanic' device as such,
because it has a firmware/hypervisor facility with roughly the same
purpose.  The 'ibm,os-term' RTAS call notifies the hypervisor that the
guest has crashed.

Our implementation of this call was sending a GUEST_PANICKED qmp event;
however, it was not doing the other usual panic actions, making its
behaviour different from pvpanic for no good reason.

To correct this, we should call qemu_system_guest_panicked() rather than
directly sending the panic event.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NThomas Huth <thuth@redhat.com>

hw/ppc/spapr_rtas.c

@@ -293,12 +293,9 @@ static void rtas_ibm_os_term(PowerPCCPU *cpu,
                             target_ulong args,
                             uint32_t nret, target_ulong rets)
 {
-    target_ulong ret = 0;
+    qemu_system_guest_panicked(NULL);
 
-    qapi_event_send_guest_panicked(GUEST_PANIC_ACTION_PAUSE, false, NULL,
-                                   &error_abort);
-
-    rtas_st(rets, 0, ret);
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
 }
 
 static void rtas_set_power_level(PowerPCCPU *cpu, sPAPRMachineState *spapr,