[U-Boot] DNS323 (Orion5x) must double ORION5X_SZ_BOOTROM to access full flash

[Rogan Dawes]

Hi Albert,

I've been trying to figure out why I could not erase sectors in my flash
greater than SA70. It turned out that this was on a megabyte boundary,
and in fact, was exactly half way through my flash.

The flash is a 64Mbit part, i.e. 8MB, and I could only access the first
4MB of it, even though the ORION5X_SZ_BOOTROM parameter was set to (8 *
1024 * 1024). By "access" I mean that even md.b commands simply returned
"00", and flash erase commands returned immediately without actually
doing anything.

Doubling the value for ORION5X_SZ_BOOTROM allowed me to access the
additional sectors, but that makes me wonder what the reason for it is.

I know that the flash chip is wired up strangely, but would that also
affect the window mappings? If that is the case, I just need to document
WHY the parameter is doubled, but if not, it would be good to understand
the real reason for the change.

Rogan