fs/adfs: dir: improve compiler coverage in adfs_dir_update

Get rid of the ifdef, using IS_ENABLED() instead to detect whether the
code should be callable.  This allows the compiler to always parse the
following code, reducing the chances of errors being missed.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/adfs/dir.c

@@ -287,14 +287,16 @@ adfs_readdir(struct file *file, struct dir_context *ctx)
 int
 adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
 {
-	int ret = -EINVAL;
-#ifdef CONFIG_ADFS_FS_RW
 	const struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
 	struct adfs_dir dir;
+	int ret;
 
 	printk(KERN_INFO "adfs_dir_update: object %06x in dir %06x\n",
 		 obj->indaddr, obj->parent_id);
 
+	if (!IS_ENABLED(CONFIG_ADFS_FS_RW))
+		return -EINVAL;
+
 	if (!ops->update)
 		return -EINVAL;
 
@@ -328,7 +330,7 @@ adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
 		adfs_dir_forget(&dir);
 unlock:
 	up_write(&adfs_dir_rwsem);
-#endif
+
 	return ret;
 }