etnaviv: submit full struct drm_etnaviv_gem_submit

It is safe to submit the full struct even on older kernels as such
kernels do not process the full struct. Without this change it
becomes quite challenging to extned the submit struct.

Freedreno has no special treatment too. See git commits
- freedreno: sync uapi header
- freedreno: add fence fd support

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>