intel_extreme: Tab cleanup; no functional change.

* It seems like the Atom editor has been injecting
spaces in strange spots.
* Clean up spaces. Should help gcc6 as well.
* Sorry for the mess! Atom is on probation.

intel_extreme: Correct generations based on some Intel help

intel_extreme: Rework card identification defines

* Be more verbose on flag type
* Add additional groups
* Add additional families
* Correctly assign later models

intel_extreme: Intial work for ValleyView support

* No impact to non-ValleyView chipsets
* Bump some register locations for VLV
* Only have HDMI port to test with on my ValleyView GPU
and our driver seems to be missing all HDMI and
sideband functionality.
* As ValleyView chipsets seem to be UEFI only, we don't
have VESA fallback, so this shouldn't cause regressions.
(unless we get UEFI framebuffer support)

intel_extreme: Add RC6 downclocking support

* Generation 6 (SandyBridge) and later support
automatic downclocking of the GPU offering
substantial battery use reductions.
* As we're playing with fire here, only use on
mobile devices SandyBridge or later.
* This is testing stable on my SandyBridge laptop,
however I need further confirmation of the
functionality of this.
* Move clock gating into a function in the power.cpp
file

intel_extreme: Add RC6 downclocking support

* Generation 6 (SandyBridge) and later support
automatic downclocking of the GPU offering
substantial battery use reductions.
* As we're playing with fire here, only use on
mobile devices SandyBridge or later.
* This is testing stable on my SandyBridge laptop,
however I need further confirmation of the
functionality of this.
* Move clock gating into a function in the power.cpp
file