Mesa RadeonSI Lands Possible Vega/Raven Performance Improvement

Earlier this month AMD's Marek OlAik posted RadeonSI patches for a scissor workaround affecting GFX9/Vega GPUs including Raven Ridge, which were based upon a RADV driver workaround already merged that helped affected games by up to ~11%. A revised version of that patch is now in Mesa 18.2 Git...