anv: Implement VK_EXT_external_memory_dma_buf

This is a modified version of the patch originally sent by Chad Versace.
The primary difference is that this version claims that OPQAUE_FD and
DMA_BUF are compatible handle types.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Chad Versace <chadversary@chromium.org>

src/intel/vulkan/anv_extensions.py

@@ -86,6 +86,7 @@ EXTENSIONS = [
     Extension('VK_KHR_xlib_surface',                      6, 'VK_USE_PLATFORM_XLIB_KHR'),
     Extension('VK_KHX_multiview',                         1, True),
     Extension('VK_EXT_debug_report',                      8, True),
+    Extension('VK_EXT_external_memory_dma_buf',           1, True),
 ]
 
 class VkVersion: