Adding OpenWrt support for Mikrotik SXTG-2HnD v2

No guarantee the pads are even connected to the SoC.

The tricky part is working out what they refer to it (in source) as. You should be able to find this from the SPI NOR hard_config data type 0x17 (board_type in prom.c): https://github.com/john-tho/linux/blob/708fc99a000d4a7fef9fa0e19caf857f2634caf0/arch/mips/rb/prom.c We know is has G (gigabit ethernet), SPI touch screen controller (voltage), buzzer, NOR. https://github.com/john-tho/linux/blob/708fc99a000d4a7fef9fa0e19caf857f2634caf0/arch/mips/rb/platform.c The way they bundle devices together with hardware options to enable/disable parts also complicates thing.

I used this on a hapac to dump SoC registers (busybox devmem).