drm/i915: Make GuC log part of the uC error state

drm/i915: Make GuC log part of the uC error state

We keep details of GuC and HuC in separate error state struct.
Make GuC log part of it to group all related data together.
Since we are printing uC details at the end, with this change
GuC log will be moved there too.

v2: comment on new placement of the log (Chris)

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171026173657.49648-2-michal.wajdeczko@intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>