If we make sure that all the dev_priv->info usages are wrapped by
INTEL_INFO(), we can easily modify the ->info field to be structure and
not a pointer while keeping the const protection in the INTEL_INFO()
macro.

v2: Rebased onto latest drm-nightly
Suggested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>