layers: GH485, Strengthen image format validation
layers: GH485, Strengthen image format validation

CreateImage was checking that format caps weren't null, but was not
validating against color or depth/stencil attachment types.

Change-Id: Ic8996829033f552f6ef7477bdefdaba702ae2403

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