sw: spi-gpio: remove unused files

These were moved into spi.c to allow them to be inlined.

Signed-off-by: Sean Cross <sean@xobs.io>

sw/src/spi-gpio.c

@@ -1,27 +0,0 @@
-#include <stdio.h>
-#include <generated/csr.h>
-
-#include "spi-gpio.h"
-
-// static uint8_t do_mirror;
-// static uint8_t oe_mirror;
-
-// void gpioSetMode(int pin, int mode) {
-//     if (mode)
-//         oe_mirror |= 1 << pin;
-//     else
-//         oe_mirror &= ~(1 << pin);
-//     picospi_oe_write(oe_mirror);
-// }
-
-// void gpioWrite(int pin, int val) {
-//     if (val)
-//         do_mirror |= 1 << pin;
-//     else
-//         do_mirror &= ~(1 << pin);
-//     picospi_do_write(do_mirror);
-// }
-
-// int gpioRead(int pin) {
-//     return !!(picospi_di_read() & (1 << pin));
-// }