layers: Validate correct layout for STORAGE_IMAGE descriptors
layers: Validate correct layout for STORAGE_IMAGE descriptors

According to the spec "Load and store operations on storage images can only
be done on images in VK_IMAGE_LAYOUT_GENERAL layout."

This change flags an error if a STORAGE_IMAGE descriptor is updated with an
image layout other than GENERAL.

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