uninorth: use object link to pass OpenPIC object to uninorth

Now that the OpenPIC is wired up via the board, we can now remove our temporary
PIC qdev pointer property and replace it with an object link instead.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
3 files changed