[Raring][Quantal SRU] ACPI video: ignore BIOS initial backlight value

[Alex Hung]

SRU Justification:

Impact:
ACPI VGA driver reads from BIOS's _BQC during initialization and use it 
to set the brightness; however, some BIOS returns zero when it boots, 
and causes complete dark on LCD panel.

Fix:
The patch fix the bug by skipping the _BQC value and set the brightness 
to maximum.


BugLink: http://bugs.launchpad.net/bugs/1167760