anv: Add KHR_display extension to anv [v7]

anv: Add KHR_display extension to anv [v7]

This adds support for the KHR_display extension to the anv Vulkan
driver. The driver now attempts to open the master DRM node when the
KHR_display extension is requested so that the common winsys code can
perform the necessary operations.

v2: Make sure primary fd is usable

	When KHR_display is selected, we try to open the primary node
	instead of the render node in case the user wants to use
	KHR_display for presentation. However, if we're actually going
	to end up using RandR leases, then we don't care if the
	resulting fd can't be used for display, but the kernel also
	prevents us from using it for drawing when someone else has
	master.

v3:
	Simplify addition of VK_USE_PLATFORM_DISPLAY_KHR to vulkan_wsi_args

	Suggested-by: Eric Engestrom <eric.engestrom@imgtec.com>
v4:
	Adapt primary node usage to new wsi_device_init API

v5:
	Adopt Jason Ekstrand's coding conventions

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

	Remove spurious MM_PER_PIXEL define

        Suggested-by: Jason Ekstrand <jason.ekstrand@intel.com>
v6:
	Open DRM master before initializing WSI layer.

	The DRM master FD is passed to the WSI layer during
	initialization, so we need to open the device slightly earlier
	in the function.

	Close DRM master in device_finish.

	Use anv_gem_get_param to detect working master_fd instead of
	directly using the ioctl.

        Suggested-by: Jason Ekstrand <jason.ekstrand@intel.com>
v7:
	Add vkCreateDisplayModeKHR. This doesn't actually create
	new modes, it only looks to see if the requested parameters
	matches an existing mode and returns that.

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