Sensorless homing using SPI endstop

Hi!

Stepper drivers like TMC2130, TMC5160 has no DIAG1 pin soldered. If you want use sensorless homing, you have to solder new pin to DIAG1 output. These drivers have SPI and TMC has support to send endstop message through SPI and in this case you don’t need DIAG1 output.
Marlin has support for this functionality (SPI_ENDSTOP flag), it would be great to have this SPI_ENDSTOP feature on Klipper.
I like stepper drivers with SPI, because of their better customizations in Klipper config (than UART), but I hate soldering when there’s possibility to solve this feature by software. :wink: