layers:Update memory helper funcs to use BINDABLE
layers:Update memory helper funcs to use BINDABLE

When getting, setting & clearing memory bindings, work with the updated
BINDABLE superclass of IMAGE & BUFFER state objects.

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