drm/i915/guc: Enable interrupts before resuming GuC during runtime resume

GuC log streaming needs interrupts enabled prior to GuC resume but
runtime pm interrupt setup was happening post GuC resume. Fix it.
While at it, fix the unwinding of steps in the runtime suspend path.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104695


Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Marta Lofstedt <marta.lofstedt@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/1516808821-3638-2-git-send-email-sagar.a.kamble@intel.com