intelfb: use firmware EDID for mode database

Use firmware EDID for the driver's private mode database.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Cc: Sylvain Meyer <sylvain.meyer@worldonline.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Airlie <airlied@linux.ie>