anv: implement VK_KHR_timeline_semaphore

anv: implement VK_KHR_timeline_semaphore

v2: Fix inverted condition in vkGetPhysicalDeviceExternalSemaphoreProperties()

v3: Add anv_timeline_* helpers (Jason)

v4: Avoid variable shadowing (Jason)
    Split timeline wait/signal device operations (Jason/Lionel)

v5: s/point/signal_value/ (Jason)
    Drop piece of drm-syncobj timeline code (Jason)

v6: Add missing sync_fd semaphore signaling (Jason)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>