layers: Update CGP var names for style
layers: Update CGP var names for style

Changed CreateGraphicsPipeline local vars to match style guidelines.

Change-Id: I3204ce878b37ef3cb0ce58ecff00d65a4fed4f28

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools