mesa: add gfxstream-experimental to -Dvulkan-drivers

This adds gfxstream-vk as a vulkan driver to Mesa.  It
will be used in the following places:

  - Android Emulator
  - Fuchsia Emulator
  - Cloud Android
  - AAOS reference hardware
  - [a few other places]

meson amd64-build/ -Dvulkan-drivers="gfxstream-experimental" -Dgallium-drivers="" -Dopengl=false

Reviewed-by: Aaron Ruby <aruby@blackberry.com>
Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Acked-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27246>

meson_options.txt

@@ -205,7 +205,8 @@ option(
   value : ['auto'],
   choices : ['auto', 'amd', 'broadcom', 'freedreno', 'intel', 'intel_hasvk',
              'panfrost', 'swrast', 'virtio', 'imagination-experimental',
-             'microsoft-experimental', 'nouveau', 'asahi', 'all'],
+             'microsoft-experimental', 'nouveau', 'asahi',
+             'gfxstream-experimental', 'all'],
   description : 'List of vulkan drivers to build. If this is set to auto ' +
                 'all drivers applicable to the target OS/architecture ' +
                 'will be built'