ipq40xx: add Cisco Meraki MR33 Support

ipq40xx: add Cisco Meraki MR33 Support

This patch adds support for Cisco Meraki MR33

hardware highlights:

SOC:	IPQ4029 Quad-Core ARMv7 Processor rev 5 (v7l) Cortex-A7
DRAM:	256 MiB DDR3L-1600 @ 627 MHz Micron MT41K128M16JT-125IT
NAND:	128 MiB SLC NAND Spansion S34ML01G200TFV00 (106 MiB usable)
ETH:	Qualcomm Atheros AR8035 Gigabit PHY (1 x LAN/WAN) + PoE
WLAN1:	QCA9887 (168c:0050) PCIe 1x1:1 802.11abgn ac Dualband VHT80
WLAN2:	Qualcomm Atheros QCA4029 2.4GHz 802.11bgn 2:2x2
WLAN3:	Qualcomm Atheros QCA4029 5GHz 802.11a/n/ac 2:2x2 VHT80
LEDS:	1 x Programmable RGB+White Status LED (driven by Ti LP5562 on i2c-1)
	1 x Orange LED Fault Indicator (shared with LP5562)
	2 x LAN Activity / Speed LEDs (On the RJ45 Port)
BUTTON:	one Reset button
MISC:	Bluetooth LE Ti cc2650 PG2.3 4x4mm - BL_CONFIG at 0x0001FFD8
	AT24C64 8KiB EEPROM
	Kensington Lock

Serial:
	WARNING: The serial port needs a TTL/RS-232 3V3 level converter!
	The Serial setting is 115200-8-N-1. The board has a populated
	1x4 0.1" header with half-height/low profile pins.
	The pinout is: VCC (little white arrow), RX, TX, GND.

Flashing needs a serial adaptor, as well as patched ubootwrite utility
(needs Little-Endian support). And a modified u-boot (enabled Ethernet).
Meraki's original u-boot source can be found in:
<https://github.com/riptidewave93/meraki-uboot/tree/mr33-20170427>

Add images to do an installation via bootloader:
 0. open up the MR33 and connect the serial console.

 1. start the 2nd stage bootloader transfer from client pc:

  # ubootwrite.py --write=mr33-uboot.bin
  (The ubootwrite tool will interrupt the boot-process and hence
   it needs to listen for cues. If the connection is bad (due to
   the low-profile pins), the tool can fail multiple times and in
   weird ways. If you are not sure, just use a terminal program
   and see what the device is doing there.

 2. power on the MR33 (with ethernet + serial cables attached)
    Warning: Make sure you do this in a private LAN that has
    no connection to the internet.

 - let it upload the u-boot this can take 250-300 seconds -

 3. use a tftp client (in binary mode!) on your PC to upload the sysupgrade.bin
    (the u-boot is listening on 192.168.1.1)
    # tftp 192.168.1.1
    binary
    put openwrt-ipq40xx-meraki_mr33-squashfs-sysupgrade.bin

 4. wait for it to reboot

 5. connect to your MR33 via ssh on 192.168.1.1

For more detailed instructions, please take a look at the:
"Flashing Instructions for the MR33" PDF. This can be found
on the wiki: <https://openwrt.org/toh/meraki/mr33>
(A link to the mr33-uboot.bin + the modified ubootwrite is
also there)

Thanks to Jerome C. for sending an MR33 to Chris.

Signed-off-by: Chris Blake <chrisrblake93@gmail.com>
Signed-off-by: Mathias Kresin <dev@kresin.me>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>