layers: Remove PV dead code, fixup comments
layers: Remove PV dead code, fixup comments

Change-Id: I94804f0b994618982afcb344dc88b92a9bee3336

KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers