drm/amdgpu: Forward soft recovery errors to userspace

As we discussed before[1], soft recovery should be
forwarded to userspace, or we can get into a really
bad state where apps will keep submitting hanging
command buffers cascading us to a hard reset.

1: https://lore.kernel.org/all/bf23d5ed-9a6b-43e7-84ee-8cbfd0d60f18@froggi.es/


Signed-off-by: Joshua Ashton <joshua@froggi.es>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 434967aa)
Cc: stable@vger.kernel.org