Use OBJECT_DECLARE_SIMPLE_TYPE when possible

This converts existing DECLARE_INSTANCE_CHECKER usage to
OBJECT_DECLARE_SIMPLE_TYPE when possible.

$ ./scripts/codeconverter/converter.py -i \
  --pattern=AddObjectDeclareSimpleType $(git grep -l '' -- '*.[ch]')

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Paul Durrant <paul@xen.org>
Message-Id: <20200916182519.415636-6-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
diff --git a/include/hw/net/cadence_gem.h b/include/hw/net/cadence_gem.h
index 89d2dab..91ebb5c 100644
--- a/include/hw/net/cadence_gem.h
+++ b/include/hw/net/cadence_gem.h
@@ -27,9 +27,7 @@
 #include "qom/object.h"
 
 #define TYPE_CADENCE_GEM "cadence_gem"
-typedef struct CadenceGEMState CadenceGEMState;
-DECLARE_INSTANCE_CHECKER(CadenceGEMState, CADENCE_GEM,
-                         TYPE_CADENCE_GEM)
+OBJECT_DECLARE_SIMPLE_TYPE(CadenceGEMState, CADENCE_GEM)
 
 #include "net/net.h"
 #include "hw/sysbus.h"