drm/etnaviv: fix MMU context leak on GPU reset

After a reset the GPU is no longer using the MMU context and may be
restarted with a different context. While the mmu_state proeprly was
cleared, the context wasn't unreferenced, leading to a memory leak.

Cc: [e-mail] # 5.4
Reported-by: Michael Walle <[e-mail]>
Signed-off-by: Lucas Stach <[e-mail]>
Tested-by: Michael Walle <[e-mail]>
Tested-by: Marek Vasut <[e-mail]>
Reviewed-by: Christian Gmeiner <[e-mail]>

drivers/gpu/drm/etnaviv/etnaviv_gpu.c

···
 
 	gpu->fe_running = false;
 	gpu->exec_state = -1;
+	if (gpu->mmu_context)
+		etnaviv_iommu_context_put(gpu->mmu_context);
 	gpu->mmu_context = NULL;
 
 	return 0;