linux: convert to ctime accessor functions

In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Signed-off-by: Jeff Layton <[e-mail]>
Reviewed-by: Jan Kara <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Christian Brauner <[e-mail]>

include/linux/fs_stack.h

···
 {
 	dest->i_atime = src->i_atime;
 	dest->i_mtime = src->i_mtime;
-	dest->i_ctime = src->i_ctime;
+	inode_set_ctime_to_ts(dest, inode_get_ctime(src));
 }
 
 #endif /* _LINUX_FS_STACK_H */