Fix spelling in comment

replace Convery -> Convert

Cc: Paul Brook <paul@codesourcery.com>
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

hw/qdev.h

@@ -132,7 +132,7 @@ CharDriverState *qdev_init_chardev(DeviceState *dev);
 
 BusState *qdev_get_parent_bus(DeviceState *dev);
 
-/* Convery from a base type to a parent type, with compile time checking.  */
+/* Convert from a base type to a parent type, with compile time checking.  */
 #ifdef __GNUC__
 #define DO_UPCAST(type, field, dev) ( __extension__ ( { \
     char __attribute__((unused)) offset_must_be_zero[ \