drm/radeon/kms: ignore unposted GPUs with no BIOS.

If we find a GPU but we can't find its BIOS and it isn't posted,
then ignore it.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index b0efd0d..f546284 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -975,7 +975,11 @@
 	if (r)
 		return r;
 	/* Post card if necessary */
-	if (!r600_card_posted(rdev) && rdev->bios) {
+	if (!r600_card_posted(rdev)) {
+		if (!rdev->bios) {
+			dev_err(rdev->dev, "Card not posted and no BIOS - ignoring\n");
+			return -EINVAL;
+		}
 		DRM_INFO("GPU not posted. posting now...\n");
 		atom_asic_init(rdev->mode_info.atom_context);
 	}