target-lm32: Update VMStateDescription to LM32CPU

Add a vmstate_lm32_cpu referencing the previous VMStateDescription as a
sub-struct and hook it up to CPUClass::vmsd. Drop cpu_{save,load}().

Acked-by: Michael Walle <michael@walle.cc>
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/target-lm32/cpu-qom.h b/target-lm32/cpu-qom.h
index 3ba86b7..9571860 100644
--- a/target-lm32/cpu-qom.h
+++ b/target-lm32/cpu-qom.h
@@ -71,6 +71,10 @@
 
 #define ENV_OFFSET offsetof(LM32CPU, env)
 
+#ifndef CONFIG_USER_ONLY
+extern const struct VMStateDescription vmstate_lm32_cpu;
+#endif
+
 void lm32_cpu_do_interrupt(CPUState *cpu);
 
 #endif