ACPI video: fix a poor warning message

Fix a vague warning message.

https://bugzilla.kernel.org/show_bug.cgi?id=16599

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/video_detect.c

@@ -59,8 +59,8 @@ acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
 				  "support\n"));
 		*cap |= ACPI_VIDEO_BACKLIGHT;
 		if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
-			printk(KERN_WARNING FW_BUG PREFIX "ACPI brightness "
-					"control misses _BQC function\n");
+			printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
+				"cannot determine initial brightness\n");
 		/* We have backlight support, no need to scan further */
 		return AE_CTRL_TERMINATE;
 	}