ipq806x: add ipq4019 fritz4040 support

ipq806x: add ipq4019 fritz4040 support

This patch adds support for AVM FRITZ!Box 4040.

hardware highlights:

SOC:	IPQ4018 / QCA Dakota
CPU:	Quad-Core ARMv7 Processor rev 5 (v7l) Cortex-A7
DRAM:	256 MiB Nanya NT5CC128M16IP
FLASH:	32 MiB MXIC MX25L25635FMI
ETH:	Qualcomm Atheros QCA8075 Gigabit Switch (4 x LAN, 1 x WAN)
USB:	1 x 3.0 (via Synopsys DesignWare DWC3 controller in the SoC)
	1 x 2.0 (via Synopsys DesignWare DWC3 controller in the SoC)
WLAN1:	Qualcomm Atheros QCA4018 2.4GHz 802.11bgn 2:2x2
WLAN2:	Qualcomm Atheros QCA4018 5GHz 802.11a/n/ac 2:2x2
INPUT:	one WLAN and one WPS button
LEDS:	Power, WAN/Internet, WIFI, INFO (red and amber) and LAN.
Serial:
	WARNING: The serial port needs a TTL/RS-232 v3.3 level converter!
        The Serial setting is 115200-8-N-1. The SoC's serial port is right
	next to the MXIC FLASH chip. The board has a unpopulated 1x4 0.1"
	header for it. Use a multimeter to figure out the pinout!

This board currently needs an additional u-boot image in order to boot
properly. Booting with EVA isn't possible ATM.

Install Procedure:
 0. It's highly recommended to connect to the serial port.
    The serial settings are listed above.
 1. install a u-boot image for AVM Fritz!Box 4040
    (see <https://github.com/chunkeey/FritzBox-4040-UBOOT/releases> and
    <https://github.com/chunkeey/FritzBox-4040-UBOOT/blob/master/upload-to-f4040.sh>)
 2. upload the initramfs.itb image via tftp (u-boot listens to
    192.168.1.1 - use binary transfer mode!)
 3. connect to the FB4040 and use sysupgrade sysupgrade.bin
    to install the image.

Works:
	- Switch and Ethernet (99%)
        - Buttons (WLAN, WPS)
        - FLASH (1 x 32MiB NOR Chip)
        - WLAN2G and WLAN5G
        - CPUFREQ scaling
        - PRNG
        - serial
        - Crypto Accelerator
        - sysupgrade (Read the flash instructions to avoid bricking)
        - full LEDE Install (Read the flash instructions to avoid bricking)
	- LEDs (Power, WAN, Info (red and amber), LAN)
          The LEDs are connected to the QCA8075 LED ports.
	  The AR40xx driver contains a gpio-controller to
	  handle these special "GPIOs".
        - USB Both 3.0 and 2.0 ports
        - many packages from other ARMv7 boards
          (This does include the RaspberryPi Model 2!)
        - ...

Not planned:
	- WAN<->LAN short-cut
	- Qualcomm Secure Execution Environment
        - ...

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John Crispin <john@phrozen.org>