staging: greybus: remove completed GPIO conversion task from TODO

The task to convert the Greybus subsystem to the GPIO descriptor interface has been completed. A grep of the directory confirms that no consumer drivers include <linux/gpio.h> or use the legacy integer based GPIO API (gpio_request, gpio_set_value, etc).

Remove the stale entry from the TODO file.

---
 drivers/staging/greybus/TODO | 3 ---
 1 file changed, 3 deletions(-)

index 6461e0132fe3..43fb6dc3dff0 100644
@@ -1,5 +1,2 @@
-* Convert all uses of the old GPIO API from <linux/gpio.h> to the
-  GPIO descriptor API in <linux/gpio/consumer.h> and look up GPIO
-  lines from device tree or ACPI.
 * Make pwm.c use the struct pwm_ops::apply instead of ::config, ::set_polarity,
   ::enable and ::disable.

2.39.5