radv: Create single RADV_DEBUG env var.

radv: Create single RADV_DEBUG env var.

Also changed RADV_SHOW_QUEUES to a no compute queue option. That
would make more sense later when the compute queue is established,
but the transfer queue still experimental.

v2: Don't include the trace flag.

Signed-off-by: Bas Nieuwenhuizen <basni@google.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>