The first 128 MiB of RAM can be accessed using an alias at address 0x0.

In theory we could access whole RAM using 0x80000000 - 0xbfffffff range
(up to 1 GiB) but it doesn't seem to work on Northstar. For some reason
(hardware setup left by the bootloader maybe?) 0x80000000 - 0x87ffffff
range can't be used. I reproduced this problem on:
1) Buffalo WZR-600DHP2 (BCM47081)
2) Netgear R6250 (BCM4708)
3) D-Link DIR-885L (BCM47094)

So it seems we're forced to access first 128 MiB using alias at 0x0 and
the rest using real base address + 128 MiB offset which is 0x88000000.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Jon Mason <jon.mason@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>