s390/cio: remove duplicate struct ccw1 declaration

struct ccw1 is declared twice. One has been declared
at 21st line. Remove the duplicate.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/include/asm/ccwdev.h

@@ -152,9 +152,6 @@ extern struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
  * when new devices for its type pop up */
 extern int  ccw_driver_register   (struct ccw_driver *driver);
 extern void ccw_driver_unregister (struct ccw_driver *driver);
-
-struct ccw1;
-
 extern int ccw_device_set_options_mask(struct ccw_device *, unsigned long);
 extern int ccw_device_set_options(struct ccw_device *, unsigned long);
 extern void ccw_device_clear_options(struct ccw_device *, unsigned long);