drm/amdgpu: add ring timeout information in devcoredump

Add ring timeout related information in the amdgpu
devcoredump file for debugging purposes.

During the gpu recovery process the registered call
is triggered and add the debug information in data
file created by devcoredump framework under the
directory /sys/class/devcoredump/devcdx/

Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>