build: PR1972, Install vk_layer_dispatch_table.h hdr
build: PR1972, Install vk_layer_dispatch_table.h hdr

vk_layer.h is installed and includes it. Also, vk_layer.h is needed
to write third party layers, so I don't think not installing vk_layer.h
is an option.

Change-Id: I3e34d8484fdc5092edff3bab72991303a4aeb2c7

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