package/mesa3d: add explicit option for Gallium VDPAU state tracker

package/mesa3d: add explicit option for Gallium VDPAU state tracker

Dependencies are too complex to have them handled automatically:

- needs mesa3d platform x11:
  https://cgit.freedesktop.org/mesa/mesa/tree/meson.build?h=19.2#n452
- needs specific gallium drivers:
  https://cgit.freedesktop.org/mesa/mesa/tree/meson.build?h=19.2#n459

Fixes:
http://autobuild.buildroot.net/results/a2c/a2c120193f5bace3a8bbcfa728dae7e290e15d6c/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
[Arnout: fix check-package issue]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>