Switch the few remaining ds_get_* uses in console.c over to the new
surface_* accessors.
While doing so tripped over a few leftovers from commit
a93a4a226a (code using depth == 0
as indicator for textmode rendering). Fixed them up.
Finally dropped ds_get_* helper helpers.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>