drm/panel: ilitek-ili9881c: Fix warning with GPIO controllers that sleep

The ilitek-ili9881c controls the reset GPIO using the non-sleeping
gpiod_set_value() function. This complains loudly when the GPIO
controller needs to sleep. As the caller can sleep, use
gpiod_set_value_cansleep() to fix the issue.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240317154839.21260-1-laurent.pinchart@ideasonboard.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240317154839.21260-1-laurent.pinchart@ideasonboard.com