ipq40xx: add support for Cell C RTL30VW

ipq40xx: add support for Cell C RTL30VW

Cell C RTL30VW is a LTE router with tho gigabit ethernets and integrated
QMI mPCIE modem.

This is stripped version of ASKEY RTL0030VW.

Hardware:

Specification:
-CPU: IPQ4019
-RAM: 256MB
-Flash: NAND 128MB + NOR 16MB
-WiFi: Integrated bgn/ac
-LTE: mPCIe card (Modem chipset MDM9230)
-LAN: 2 Gigabit Ports
-USB: 2x USB2.0
-Serial console: RJ-45 115200 8n1
-Unsupported VoIP

Known issues:

None so far.

Instruction install:

There are two methods: Factory web-gui and serial + tftp.

Web-gui:
1. Apply factory image via stock web-gui.

Serial + initramfs:
1. Rename OpenWrt initramfs image to "image"
2. Connect serial console (115200,8n1)
3. Set IP to different than 192.168.1.11, but 24 bit mask, eg. 192.168.1.4.

4. U-Boot commands:
sf probe && sf read 0x80000000 0x180000 0x10000
setenv serverip 192.168.1.4
set fdt_high 0x85000000
tftpboot 0x84000000 image
bootm 0x84000000

5. Install sysupgrade image via "sysupgrade -n"

Back to stock:

All is needed is swap 0x4c byte in mtd8 from 0 to 1 or 1 to 0,
do firstboot and factory reset with OFW:

1. read mtd8:
dd if=/dev/mtd8 of=/tmp/mtd8
2. go to tmp:
cd /tmp/
3. write first part of partition:
dd if=mtd8 of=mtd8.new bs=1 count=76
4. check which layout uses bootloader:
cat /proc/mtd
5a. If first are kernel_1 and rootfs_1 write 0:
echo -n -e '\x00' >> mtd8.new
5b. If first are kernel and rootfs write 1:
echo -n -e '\x01' >> mtd8.new
6. fill with rest of data:
dd if=mtd8 bs=1 skip=77 >> mtd8.new
7. CHECK IF mtd8.new HAVE CHANGED ONLY ONE BYTE! e.g with:
hexdump mtd8.new
8. write new mtd8 to flash:
mtd write mtd8.new /dev/mtd8
9. do firstboot
10.reboot
11. Do back to factory defaults in OFW GUI.

Based on work: Cezary Jackiewicz <cezary@eko.one.pl>

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>