Another pass on Workarounds, with a focus on HSW

[damien.lespiau at intel.com (Damien Lespiau)]

Hi,

Patches 1-7: Some comments to signal the Wa we're implementing for the next
person that goes through the list.

Patch 8: Random detail when reading that code

Patch 9-10: Two new workarounds. I don't remember at all the discussions around
RC6+ on GEN6+, but there's definitely a workaround that tells us to disable
RC6+.

-- 
Damien