[PATCH 6/7] New utility ubidump

[hujianyang]

> 
> This is why I suggest to start small, do just the UBIFS nodes dump,
> nothing else. Just forget about UBI. Then let's review that and make
> part of mtd-utils. This will clarify the vision, and we may add UBI
> support then separately.
>

So just use simple way to do UBIFS dump and then step by step
make it a strong utility.

It's not too hard. I will first realize an UBIFS dump as you
showed by mtd driver.