drm/i915: demote opregion excessive timeout WARN_ONCE to DRM_INFO_ONCE
The WARN_ONCE is a bit too verbose, make it a DRM_INFO_ONCE.
While at it, add a #define for MAX_DSLP and make the message a bit more
informative.
v2: use DRM_INFO_ONCE, add MAX_DSLP, pimp the message.
Suggested-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>