[ARM] mv78xx: wrong cpu1 window base register address

The constant DDR_WINDOW_CPU1_BASE has wrong value.
Because of that mv78xx0_mbus_dram_info is not filled properly on
start, and in its turn drivers, that used mv78xx0_mbus_dram_info,
in my case mv643xx_eth.c, not work on second core.
According to

MV76100, MV78100, and MV78200 DiscoveryTM Innovation Series
CPU Family Functional Specifications

address should be 0x1570.

Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Acked-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>