Revert "ACPI / video: change acpi-video brightness_switch_enabled default to 0"

This reverts commit 886129a8eebeb (ACPI / video: change acpi-video
brightness_switch_enabled default to 0) as it is reported to cause
problems to happen.

Fixes: 886129a8eebeb (ACPI / video: change acpi-video brightness_switch_enabled default to 0)
Link: http://marc.info/?l=linux-acpi&m=140534286826819&w=2
Reported by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation/kernel-parameters.txt

@@ -3526,7 +3526,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			the allocated input device; If set to 0, video driver
 			will only send out the event without touching backlight
 			brightness level.
-			default: 0
+			default: 1
 
 	virtio_mmio.device=
 			[VMMIO] Memory mapped virtio (platform) device.

drivers/acpi/video.c

@@ -68,7 +68,7 @@ MODULE_AUTHOR("Bruno Ducrot");
 MODULE_DESCRIPTION("ACPI Video Driver");
 MODULE_LICENSE("GPL");
 
-static bool brightness_switch_enabled;
+static bool brightness_switch_enabled = 1;
 module_param(brightness_switch_enabled, bool, 0644);
 
 /*