Unbreak the handling of ATAPI CD media catalogues.

--- /usr/src/sys/dev/ata/atapi-cd.c	2001/01/29 18:07:18	1.48.2.9
+++ /usr/src/sys/dev/ata/atapi-cd.c	2001/02/21 01:42:14
@@ -730,6 +730,11 @@
 			       sizeof(cdp->subchan)>>8, sizeof(cdp->subchan),
 			       0, 0, 0, 0, 0, 0, 0 };
 
+	    if (args->data_format != CD_CURRENT_POSITION) {
+		error = ENODEV;
+		break;
+	    }
+
 	    if (len > sizeof(data) ||
 		len < sizeof(struct cd_sub_channel_header)) {
 		error = EINVAL;