ACPI video: ignore BIOS initial backlight value for HP 1000

On HP 1000 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References:: https://bugs.launchpad.net/bugs/1167760


Signed-off-by: Alex Hung <alex.hung@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>