ACPI / video: ignore BIOS initial backlight value for Fujitsu E753

The BIOS of FUjitsu E753 reports an incorrect initial backlight value
for WIN8 compatible OS, causing backlight to be dark during startup.
This change causes the incorrect initial value from BIOS to be ignored.

References: https://bugzilla.kernel.org/show_bug.cgi?id=60161
Reported-and-tested-by: Jan Hinnerk Stosch <janhinnerk.stosch@gmail.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Cc: 3.7+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>