drm/panel/lg-sw43408: mark sw43408_backlight_ops as static

Fix sparse warning regarding symbol 'sw43408_backlight_ops' not being
declared.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Reviewed-by: Neil Armstrong <[email protected]>
Fixes: 069a6c0 ("drm: panel: Add LG sw43408 panel driver")
Reviewed-by: Marijn Suijten <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Dmitry Baryshkov <[email protected]>

Author: lumag

drivers/gpu/drm/panel/panel-lg-sw43408.c

@@ -182,7 +182,7 @@ static int sw43408_backlight_update_status(struct backlight_device *bl)
 	return mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
 }
 
-const struct backlight_ops sw43408_backlight_ops = {
+static const struct backlight_ops sw43408_backlight_ops = {
 	.update_status = sw43408_backlight_update_status,
 };