platform/x86: dell-uart-backlight: Make dell_uart_bl_serdev_driver static

Sparse reports:

dell-uart-backlight.c:328:29: warning: symbol
'dell_uart_bl_serdev_driver' was not declared. Should it be static?

Fix it by making the symbol static.

Fixes: 484bae9 ("platform/x86: Add new Dell UART backlight driver")
Reviewed-by: Mario Limonciello <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ilpo Järvinen <[email protected]>
Reviewed-by: Ilpo Järvinen <[email protected]>

Author: ij-intel

drivers/platform/x86/dell/dell-uart-backlight.c

@@ -325,7 +325,7 @@ static int dell_uart_bl_serdev_probe(struct serdev_device *serdev)
 	return PTR_ERR_OR_ZERO(dell_bl->bl);
 }
 
-struct serdev_device_driver dell_uart_bl_serdev_driver = {
+static struct serdev_device_driver dell_uart_bl_serdev_driver = {
 	.probe = dell_uart_bl_serdev_probe,
 	.driver = {
 		.name = KBUILD_MODNAME,