get rid of cred argument of vfs_open() and do_dentry_open()

always equal to ->f_cred

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/internal.h b/fs/internal.h
index 661c314..baeab53 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -126,7 +126,7 @@
 		int flag);
 
 extern int open_check_o_direct(struct file *f);
-extern int vfs_open(const struct path *, struct file *, const struct cred *);
+extern int vfs_open(const struct path *, struct file *);
 
 /*
  * inode.c