auxiliary/vl: bring back the VL code for the dri targets

auxiliary/vl: bring back the VL code for the dri targets

With commit c642e87d9f4(auxiliary/vl: rework the build of the VL code)
we split out the VL code into a separate static library that was meant
to be used by the VL targets alone - va, vdpau, xvmc.

The commit failed to consider the way we handle vdpau-gl interop and
broke it. Bring back the functionality by keeping the vl <> vl_stub
separation as requrested by Christian.

v2: Update the omx target as well. Update mesa-stable email address.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86837
Cc: "10.5" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Tested-by: Andy Furniss <adf.lists@gmail.com>