cpu: Fix cpu_class_set_vmsd() documentation

It's CPUClass::vmsd, not CPUState::vmsd.

Reviewed-by: liguang <lig.fnst@cn.fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

include/qom/cpu.h

diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index a5bb515..55a85c1 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -226,7 +226,7 @@
  *
  * The @value argument is intentionally discarded for the non-softmmu targets
  * to avoid linker errors or excessive preprocessor usage. If this behavior
- * is undesired, you should assign #CPUState.vmsd directly instead.
+ * is undesired, you should assign #CPUClass.vmsd directly instead.
  */
 #ifndef CONFIG_USER_ONLY
 static inline void cpu_class_set_vmsd(CPUClass *cc,