i8257: Move QOM macro to header

Move the I8257 macro to i8257.h, close to the TYPE_I8257 define.

This will make future conversion to OBJECT_DECLARE* easier.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Tested-By: Roman Bolshakov <r.bolshakov@yadro.com>
Message-Id: <20200825192110.3528606-32-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

hw/dma/i8257.c

@@ -33,8 +33,6 @@
 #include "qemu/log.h"
 #include "trace.h"
 
-#define I8257(obj) \
-    OBJECT_CHECK(I8257State, (obj), TYPE_I8257)
 
 /* #define DEBUG_DMA */
 

include/hw/dma/i8257.h

@@ -5,6 +5,8 @@
 #include "exec/ioport.h"
 
 #define TYPE_I8257 "i8257"
+#define I8257(obj) \
+    OBJECT_CHECK(I8257State, (obj), TYPE_I8257)
 
 typedef struct I8257Regs {
     int now[2];