nitb: The subscr->imsi is an array will never be NULL

Array compared against 0 (NO_EFFECT)
array_null: Comparing an array to null is not useful: "subscr->imsi"

Fixes: Coverity CID 1040716
diff --git a/openbsc/src/libmsc/vty_interface_layer3.c b/openbsc/src/libmsc/vty_interface_layer3.c
index 6b83275..393844e 100644
--- a/openbsc/src/libmsc/vty_interface_layer3.c
+++ b/openbsc/src/libmsc/vty_interface_layer3.c
@@ -65,8 +65,7 @@
 			VTY_NEWLINE);
 	vty_out(vty, "    LAC: %d/0x%x%s",
 		subscr->lac, subscr->lac, VTY_NEWLINE);
-	if (subscr->imsi)
-		vty_out(vty, "    IMSI: %s%s", subscr->imsi, VTY_NEWLINE);
+	vty_out(vty, "    IMSI: %s%s", subscr->imsi, VTY_NEWLINE);
 	if (subscr->tmsi != GSM_RESERVED_TMSI)
 		vty_out(vty, "    TMSI: %08X%s", subscr->tmsi,
 			VTY_NEWLINE);