drm/i915: Add pretty printer for runtime part of intel_device_info

During initialization of the runtime part of the intel_device_info
we are dumping that part using DRM_DEBUG_DRIVER mechanism.
As we already have pretty printer for const part of the info,
make similar function for the runtime part and use it separately.

v2: add runtime dump to debugfs (Chris)

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171221185334.17396-7-michal.wajdeczko@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/20171221215735.30314-6-chris@chris-wilson.co.uk