drm/etnaviv: replace license text with SPDX tags

This replaces the repetitive GPL-2.0 license text in code and header files
with the SPDX tags. Generated hardware headers aren't changed, as any changes
there need to be done in the upstream rnndb repository.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

drm/etnaviv: use submit exec_state for perfmon sampling

The GPU exec state may have changed at the time when the perfmon sampling
is done, as it reflects the state of the last submission, not the current
GPU execution state.

So for proper sampling we must use the submit exec_state.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: add performance monitor request processing

Changes v4 -> v5
- make use of doms_meta array

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: add performance monitor request validation

Check if the selected domain and signal combination exists.

Changes from v4 to v5
- add exec_state parameter

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: add internal representation of perfmon_request

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drm/etnaviv: add infrastructure to query perf counter

Make it possible that userspace can query all performance domains and
its signals. This information is needed to sample those signals via
submit ioctl.

At the moment no performance domain is available.

Changes from v1 -> v2:
- use a 16 bit value for signals
- fix padding issues
- add id member to domain and signal struct

Changes v4 -> v5
- provide for each pipe an own set of pm domains

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>