drm/i915: Add a more detailed comment about the set_base() fastboot hack

Instead of it just being on the mailing list, let's put Jesse's
explanation next to the code in question.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 file changed