pmb.qemu.run.install_depends: Fix Mesa Gallium DRI depends

Commit 43520967 ("pmb.qemu.run.install_depends: adjust to mesa pkgs (!1865 (merged))") replaced mesa-dri-swrast, mesa-dri-virtio and mesa-dri-vmwgfx with mesa-va-gallium. But the Gallium DRI drivers are actually provided by mesa-dri-gallium. mesa-va-gallium contains libva drivers for hardware video acceleration.

Fortunately this did not break anything because mesa-dri-gallium was still installed as dependency of mesa-dri-ati/intel/nouveau.

QEMU does not make use of libva, so lets just replace mesa-va-gallium with mesa-dri-gallium. While we are at it, stop depending on the deprecated mesa-dri-ati/intel/nouveau packages. Those are only kept for compatibility reasons and install more dependencies than necessary.

Cc: @ollieparanoid