An update for the i915 GPU driver, which brings the code up to Linux
commit 4d93914ae3db4a897ead4b.
MFC r277959 (by adrian):
Fix backlight for ivybridge based laptops (and whatever else comes through
this codepath.)
MFC r278146:
Do not attach to the unsupported chipsets, unless magic tunable is
frobbed.
MFC r278147, r278148:
Fix sign for the error code returned from the driver-specific code.
MFC r278152:
Do not access gmbus_ports array past its end.
MFC r278159 (by emaste):
Remove duplicate intel_fbc_enabled prototype.
571ee1f33d