drm/edid: use for_each_displayid_db where applicable

Replace the duplicated versions of the while loop with the new macro.

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190619183033.6922-1-andresx7@gmail.com