icd: Enable the VK_KHR_push_descriptor extension
icd: Enable the VK_KHR_push_descriptor extension

Enabled this extension and updated vkGetPhysicalDeviceProperties2KHR to
fill out the push descriptor properties struct if it's in the pNext
chain.

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