drm/radeon: add GET_PARAM/INFO support for Z pipes

Needed for occlusion queries on rv530 chips.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_state.c b/drivers/gpu/drm/radeon/radeon_state.c
index 46645f3..2882f40 100644
--- a/drivers/gpu/drm/radeon/radeon_state.c
+++ b/drivers/gpu/drm/radeon/radeon_state.c
@@ -3081,6 +3081,9 @@
 	case RADEON_PARAM_NUM_GB_PIPES:
 		value = dev_priv->num_gb_pipes;
 		break;
+	case RADEON_PARAM_NUM_Z_PIPES:
+		value = dev_priv->num_z_pipes;
+		break;
 	default:
 		DRM_DEBUG("Invalid parameter %d\n", param->param);
 		return -EINVAL;