drm/i915/guc: Extract GuC error capture lists on G2H notification.

- Upon the G2H Notify-Err-Capture event, parse through the
  GuC Log Buffer (error-capture-subregion) and generate one or
  more capture-nodes. A single node represents a single "engine-
  instance-capture-dump" and contains at least 3 register lists:
  global, engine-class and engine-instance. An internal link
  list is maintained to store one or more nodes.
- Because the link-list node generation happen before the call
  to i915_gpu_codedump, duplicate global and engine-class register
  lists for each engine-instance register dump if we find
  dependent-engine resets in a engine-capture-group.
- When i915_gpu_coredump calls into capture_engine, (in a
  subsequent patch) we detach the matching node (guc-id,
  LRCA, etc) from the link list above and attach it to
  i915_gpu_coredump's intel_engine_coredump structure when have
  matching LRCA/guc-id/engine-instance.

Additional notes to be aware of:
- GuC generates the error capture dump into the GuC log buffer but
  this buffer is one big log buffer with 3 independent subregions
  within it. Each subregion is populated with different content
  and used in different ways and timings but all regions operate
  behave as independent ring buffers. Each guc-log subregion
  (general-logs, crash-dump and error- capture) has it's own
  guc_log_buffer_state that contain independent read and write
  pointers.

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321164527.2500062-11-alan.previn.teres.alexis@intel.com