etnaviv: add some helpers

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
etnaviv: we need to keep track of relocs

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
etnaviv: lets start with copy&paste from freedreno

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
etnaviv: its a good idea to do a reset after flush

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
etnaviv: with small steps to success

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>