mvebu: cortexa9: Add support for Ctera C200-V2

2-Bay NAS - maximum two 3.5" Harddisks

Hardware:
  - SoC: Marvell 88F6707-A1 ARMv7 Processor 1,2GHz (ARMADA 370 SoC)
  - Ram: 1GB (2x Nanya NT5CC512M8DN-D1)
  - NAND Flash: 256MB (ESMT F59L2G81A-25T)
  - Lan: 1x GBE (Marvell 88E1318-NNB2)
  - Storage: 2x SATA HDD 3.5" Slot
  - USB: 2x USB 3.0 port (Renesas uPD720202)
  - Console: Internal J3 connector (1: Vcc, 2: Rx, 3: Tx, 4: GND)
  - LEDs: 13x GPIO controlled
  - Buttons: 2x GPIO controlled

Known issues:
  - Buzzer is unused due lack of proper driver
  - USB1/2 usbport ledtrigger won't work (through DT)
  - Renesas uPD720202 requires firmware file. It's possible to find
    non-free binary. Please look for 'UPDATE.mem' file and put in into
    '/lib/firmware/renesas_usb_fw.mem' file.

Installation:
  - Apply factory initramfs image via stock web-gui.
  - Do sysupgrade to make installation complete.

Back to stock:
  - OpenWrt rootfs partition use unused space after stock firmware.
  - Full revert is possible.
  - Login via ssh and run:

 ## ctera_c200-v2_back_to_factory start ##
 . /lib/functions.sh
 part=$(find_mtd_part "active_bank")
 active_bank=$(strings "$part" | grep bank)
 if [ "$active_bank" = "bank1" ]; then
 	echo "bank2" > /tmp/change_bank
 else
 	echo "bank1" > /tmp/change_bank
 fi
 mtd write /tmp/change_bank active_bank
 reboot
 ## ctera_c200-v2_back_to_factory end ##

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
(put back-to-stock script into commit message, removed dup. SUBPAGESIZE var,
added 01_leds for non-working dt-usb-port trigger)
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>