powerpc/83xx: Add support for MPC8377E-WLAN boards

MPC8377E-WLAN are basically RDB boards except:

- RAM extended to 512 MB;
- NAND flash removed, NOR flash extended to 64 MB;
- Vitesse VSC7385 5-port switch removed, RTL8211B PHY added;
- Power management MCU removed;
- PCI slot removed, another mini-PCI slot added (IRQ routing changed);
- USB3300 PHY's ID pin grounded, thus USB port is host-only.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>