drm: remove the raw_edid field from struct drm_display_info

Neither the drm core nor any of the drivers really need the raw_edid field
of struct drm_display_info for anything. Instead of being useful, it
creates confusion about who is responsible for freeing the memory it points
to and setting the field to NULL afterwards, leading to memory leaks and
dangling pointers.

Remove the raw_edid field, and fix drivers as necessary.

Reported-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>