XPT2046 Software SPI Touch Driver

A kernel driver for the XPT2046 resistive touch controller, bit-banged over plain GPIO pins instead of a hardware SPI peripheral. Use this instead of xpt2046-module when no SPI host is free for touch (e.g. both SPI2_HOST and SPI3_HOST are already claimed by the display and an SD card).

No reset or interrupt pin support (matches the controller's typical wiring: polled, no dedicated IRQ line wired on most panels using it).