kvm: Actually remove software breakpoints from list on cleanup

So far we only removed them from the guest, leaving its states in the
list. This made it impossible for gdb to re-enable breakpoints on the
same address after re-attaching.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

kvm-all.c

@@ -1905,6 +1905,8 @@ void kvm_remove_all_breakpoints(CPUArchState *current_env)
                 }
             }
         }
+        QTAILQ_REMOVE(&s->kvm_sw_breakpoints, bp, entry);
+        g_free(bp);
     }
     kvm_arch_remove_all_hw_breakpoints();