autofs: remove duplicated AUTOFS_DEV_IOCTL_SIZE definition

This macro is already defined in uapi header.  Also use this macro where
possible.

Link: http://lkml.kernel.org/r/148577166656.9801.10322423666945951186.stgit@pluto.themaw.net
Signed-off-by: Tomohiro Kusumi <tkusumi@tuxera.com>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs4/dev-ioctl.c

@@ -38,8 +38,6 @@
  * which have been left busy at at service shutdown.
  */
 
-#define AUTOFS_DEV_IOCTL_SIZE	sizeof(struct autofs_dev_ioctl)
-
 typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
 			struct autofs_dev_ioctl *);
 

include/uapi/linux/auto_dev-ioctl.h

@@ -113,10 +113,10 @@ struct autofs_dev_ioctl {
 
 static inline void init_autofs_dev_ioctl(struct autofs_dev_ioctl *in)
 {
-	memset(in, 0, sizeof(struct autofs_dev_ioctl));
+	memset(in, 0, AUTOFS_DEV_IOCTL_SIZE);
 	in->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
 	in->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
-	in->size = sizeof(struct autofs_dev_ioctl);
+	in->size = AUTOFS_DEV_IOCTL_SIZE;
 	in->ioctlfd = -1;
 }