target-xtensa: QOM'ify CPU

Embed CPUXtensaState as first member of XtensaCPU.
Let CPUClass::reset() call cpu_state_reset() for now.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
diff --git a/target-xtensa/helper.c b/target-xtensa/helper.c
index dab135c..20338e6 100644
--- a/target-xtensa/helper.c
+++ b/target-xtensa/helper.c
@@ -95,6 +95,7 @@
 {
     static int tcg_inited;
     static int debug_handler_inited;
+    XtensaCPU *cpu;
     CPUXtensaState *env;
     const XtensaConfig *config = NULL;
     XtensaConfigList *core = xtensa_cores;
@@ -109,7 +110,8 @@
         return NULL;
     }
 
-    env = g_malloc0(sizeof(*env));
+    cpu = XTENSA_CPU(object_new(TYPE_XTENSA_CPU));
+    env = &cpu->env;
     env->config = config;
     cpu_exec_init(env);