maybe etna_context_flush(..) does something useful now (only compile tested)

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
store fence number returned by submit ioctl

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
bring etna_pipe_wait(..) to life

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
fix etna_context_finish(..)

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
do not automatically delete bos after submit

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