rename osim_file_find_* to osim_file_desc_find_*

they return an osim_file_desc, and not an osim_file, so fix the naming
diff --git a/utils/osmo-sim-test.c b/utils/osmo-sim-test.c
index d6299e9..e861748 100644
--- a/utils/osmo-sim-test.c
+++ b/utils/osmo-sim-test.c
@@ -276,7 +276,7 @@
 
 		/* attach the USIM profile, FIXME: do this based on AID match */
 		st->card->prof = osim_cprof_usim(st->card);
-		st->cwd = osim_file_find_name(st->card->prof->mf, "ADF.USIM");
+		st->cwd = osim_file_desc_find_name(st->card->prof->mf, "ADF.USIM");
 
 		msgb_free(msg);