[PATCH] nand: Fix problem with oobsize calculation

Here the description from Brian Brelsford <Brian_Brelsford@dell.com>:

The Hynix part returns a 0x1d in the 4th ID byte. The Samsung part
returns a 0x15. In the code fragment below bits [1:0] determine the
page size, it is ANDed via "(extid & 0x3)" then shifted out. The
next field is also ANDed with 0x3. However this is a one bit field
as defined in the Hynix and Samsung parts in the 4th ID byte that
determins the oobsize, not a two bit field. It works on Samsung as
bits[3:2] are 01. However for the Hynix there is a 11 in these two
bits, so the oob size gets messed up.

I checked the correct linux code and the suggested fix from Brian is
also available in the linux nand mtd driver.

Signed-off-by: Stefan Roese <sr@denx.de>