drm/panel: ili9341: Correct use of device property APIs

drm/panel: ili9341: Correct use of device property APIs

It seems driver missed the point of proper use of device property APIs.
Correct this by updating headers and calls respectively.

Fixes: 5a04227326b0 ("drm/panel: Add ilitek ili9341 panel driver")
Signed-off-by: Andy Shevchenko <[email protected]>
Reviewed-by: Dmitry Baryshkov <[email protected]>
Reviewed-by: Neil Armstrong <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Neil Armstrong <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]