backlight: Allow properties to be passed at registration

Values such as max_brightness should be set before backlights are
registered, but the current API doesn't allow that. Add a parameter to
backlight_device_register and update drivers to ensure that they
set this correctly.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
diff --git a/drivers/platform/x86/compal-laptop.c b/drivers/platform/x86/compal-laptop.c
index 2740b40..71ff154 100644
--- a/drivers/platform/x86/compal-laptop.c
+++ b/drivers/platform/x86/compal-laptop.c
@@ -291,12 +291,15 @@
 	/* Register backlight stuff */
 
 	if (!acpi_video_backlight_support()) {
-		compalbl_device = backlight_device_register("compal-laptop", NULL, NULL,
-							    &compalbl_ops);
+		struct backlight_properties props;
+		memset(&props, 0, sizeof(struct backlight_properties));
+		props.max_brightness = COMPAL_LCD_LEVEL_MAX - 1;
+		compalbl_device = backlight_device_register("compal-laptop",
+							    NULL, NULL,
+							    &compalbl_ops,
+							    &props);
 		if (IS_ERR(compalbl_device))
 			return PTR_ERR(compalbl_device);
-
-		compalbl_device->props.max_brightness = COMPAL_LCD_LEVEL_MAX-1;
 	}
 
 	ret = platform_driver_register(&compal_driver);