qualcommax: ipq807x: add support for TCL LINKHUB HH500V

qualcommax: ipq807x: add support for TCL LINKHUB HH500V

TCL LINKHUB HH500V also known as Vodafone Gigacube B157 is a dual band
802.11ax 5G NR CPE with an FXS port.

Specifications:
* SoC: Qualcomm IPQ8072A
* RAM: 1024 MB
* NAND flash: 256MB NAND (MT29F2G08ABBGAH4)
* NOR flash: 64MB NOR (MX25U25635F) - only in some variants
* WiFi 5G: Qualcomm QCN5054
* WiFi 2.4G: Qualcomm QCN5024
* Ethernet 2.5G: Qualcomm QCA8081
* Ethernet 1G: Qualcomm QCA8075
* Modem: GosunCn GM800 (Qualcomm Snapdragon X55)
* SIM: 1 nano-SIM card slot
* Buttons: Power, Reset, WPS
* LEDs: Power (B/R), WiFi (B), 4G (B/Y/R), 5G (B/Y/R)
* VoIP: 1 FXS RJ11 port (not supported in OpenWrt)
* Power: 12V, 3A

UART serial console:

* 115200,8N1,1.8V
* Three unmarked test points next to QJ2012A:

 +---------+
 | QJ2012A |
 +---------+
 o TX
 o GND
 o RX
 o
 o
 o

Installation via OEM firmware:

* Use the following process to obtain root ssh access
https://forum.openwrt.org/t/150371/24
* Connect using root with no password on port 42000
* Optionally for serial bootloader access run :
fw_setenv bootdelay=3
* SCP factory.bin to /tmp
* Run:
sysupgrade -n /tmp/factory.bin

Installation via serial console and OEM firmware::

* Use console to access OEM firmware shell
* Proceed with SCP & sysupgrade as described above

Other notes:

* This device uses active partition rotation
* Some versions (TCL branded?) have a NOR chip in addition to NAND
* The above is supported by u-boot patching DT partitions
* DT patching does NOT occur on tftpboot/bootm
* Modem is detected as foxconn-sdx55 by kernel (same VID/PID)
* This works OK-ish and should be improved if we can get OEM modem details

Signed-off-by: Milan Krstic <milan.krstic@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/19182
Signed-off-by: Robert Marko <robimarko@gmail.com>