ARM: BCM5301X: initial support for the BCM5301X/BCM470X SoCs with ARM CPU

ARM: BCM5301X: initial support for the BCM5301X/BCM470X SoCs with ARM CPU

This patch adds support for the BCM5301X/BCM470X SoCs with an ARM CPUs.
Currently just booting to a shell is working and nothing else, no
Ethernet, wifi, flash, ...
I have some pending patches to make Ethernet work for this device.
Mostly device tree support for bcma is missing.

This SoC is used in small office and home router with Broadcom SoCs
it's internal name is Northstar. This code should support the BCM4707,
BCM4708, BCM4709, BCM53010, BCM53011 and BCM53012 SoC. It uses one or
two ARM Cortex A9 Cores, some highlights are 2 PCIe 2.0 controllers,
4 Gigabit Ethernet MACs and a USB 3.0 host controller.

This SoC uses a dual core CPU, but this is currently not implemented.
More information about this SoC can be found here:
http://www.anandtech.com/show/5925/broadcom-announces-bcm4708x-and-bcm5301x-socs-for-80211ac-routers

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christian Daudt <bcm@fixthebug.org>
Signed-off-by: Matt Porter <mporter@linaro.org>