[MTD] [NAND] cafe_nand.c: the OLPC laptop is not available for $100

The price might drop to $100 in a few years.

But currently, a more reasonable name might be "$175 laptop".

Let's simply call it "OLPC laptop" without any price tag.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>