etnaviv_noop backend

This implements the minimum of etnaviv in order to make shader-db work. The submit ioctl is stubbed out to not execute anything.

Export MESA_LOADER_DRIVER_OVERRIDE=etnaviv LD_PRELOAD=$prefix/lib/libetnaviv_noop_drm_shim.so.

It is possible to select a specific GPU model by setting the ETNA_SHIM_GPU environment variable.

The following GPU models are available:

• GC2000 (default)

• GC3000

• GC7000L