This add the initial support of the broadcom reference
board bcm968580xref with a bcm6858 SoC.
This board has 512 MB of ram, 256 MB of flash (nand),
2 usb port, 1 uart, 4 ethernet ports (LAN), 1 ethernet port (WAN).
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
