cpu: drop old comments describing members

These comments are obviously stale.
Acked-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20170913132417.24384-3-david@redhat.com>
Signed-off-by: NCornelia Huck <cohuck@redhat.com>

include/qom/cpu.h

@@ -388,10 +388,10 @@ struct CPUState {
     DECLARE_BITMAP(trace_dstate, CPU_TRACE_DSTATE_MAX_EVENTS);
 
     /* TODO Move common fields from CPUArchState here. */
-    int cpu_index; /* used by alpha TCG */
-    uint32_t halted; /* used by alpha, cris, ppc TCG */
+    int cpu_index;
+    uint32_t halted;
     uint32_t can_do_io;
-    int32_t exception_index; /* used by m68k TCG */
+    int32_t exception_index;
 
     /* shared by kvm, hax and hvf */
     bool vcpu_dirty;