update README.md

update README.md

update README.md

update README.md

simple: rename simple_open

root cause commits in linux-stable:
commit 20955e891d828b2027281fe3295dae6af8e0423b
Author: Stephen Boyd <[email protected]>
Date:   Thu Apr 5 14:25:09 2012 -0700

    libfs: add simple_open()

sbull: Fix compiling warning

commits in linux-stable:
commit 5a7bbad27a410350e64a2d7f5ec18fc73836c14f
Author: Christoph Hellwig <[email protected]>
Date:   Mon Sep 12 12:12:01 2011 +0200

    block: remove support for bio remapping from ->make_request

scullc sculld: Fix return nopage falsely

[usb]: Fix bug that blocked forerver in skel_read

Using processed_urb is unnecessary,
and it cause reader blocked in skel_read/wait_for_completion
before submit bulk in urb.