drm/nv50-/disp: audit and version SOR_HDA_ELD method

The full object interfaces are about to be exposed to userspace, so we
need to check for any security-related issues and version the structs
to make it easier to handle any changes we may need in the future.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
index 869789f..9381b16 100644
--- a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
@@ -905,6 +905,10 @@
 		return priv->dac.sense(object, priv, data, size, head, outp);
 	case NV50_DISP_MTHD_V1_SOR_PWR:
 		return priv->sor.power(object, priv, data, size, head, outp);
+	case NV50_DISP_MTHD_V1_SOR_HDA_ELD:
+		if (!priv->sor.hda_eld)
+			return -ENODEV;
+		return priv->sor.hda_eld(object, priv, data, size, head, outp);
 	default:
 		break;
 	}