anv: add VK_EXT_display_control to anv driver [v5]

anv: add VK_EXT_display_control to anv driver [v5]

This extension provides fences and frame count information to direct
display contexts. It uses new kernel ioctls to provide 64-bits of
vblank sequence and nanosecond resolution.

v2:	Adopt Jason Ekstrand's coding conventions

	Declare variables at first use, eliminate extra whitespace between
	types and names. Wrap lines to 80 columns.

	Add extension to list in alphabetical order

	Suggested-by: Jason Ekstrand <jason.ekstrand@intel.com>
v3:	Adapt to WSI fence API change. It now returns VkResult and
	no longer has an option for relative timeouts.

v4:	wsi_register_display_event and wsi_register_device_event now
	use the default allocator when NULL is provided, so remove the
	computation of 'alloc' here.

v5:	use zalloc2 instead of alloc2 for the WSI fence.

	Suggested-by: Jason Ekstrand <jason.ekstrand@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>