Support VK_KHR_dedicated_allocation in Vulkan allocator

[i509VCB]

While working on the Vulkan renderer this came to mind.

Per the specification:

• requiresDedicatedAllocation may be VK_TRUE if the pNext chain of VkImageCreateInfo for the call to vkCreateImage used to create the image being queried included a VkExternalMemoryImageCreateInfo structure, and any of the handle types specified in VkExternalMemoryImageCreateInfo::handleTypes requires dedicated allocation, as reported by vkGetPhysicalDeviceImageFormatProperties2 in VkExternalImageFormatProperties::externalMemoryProperties.externalMemoryFeatures.

• requiresDedicatedAllocation may be VK_TRUE if the image’s tiling is VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT.

Since the Vulkan allocator creates images with a drm tiling and images that are exportable this is worth considering.

There are also benefits to considering the prefersDedicatedAllocation suggestion since the driver may be able to allocate with a more optimal memory type.

In the case of the allocator I would not consider this to be mandatory extension.

[i509VCB]

Further info: more than 90% of Vulkan implementations on Linux support dedicated allocations, so requiring dedicated allocations would be fine.