msc_vlr_tests.c: drop duplicating DMM category definition

Change-Id: I2bf8150580c318ccaa9c30657582c15020f6b711
diff --git a/tests/msc_vlr/msc_vlr_tests.c b/tests/msc_vlr/msc_vlr_tests.c
index fd196c8..9515c63 100644
--- a/tests/msc_vlr/msc_vlr_tests.c
+++ b/tests/msc_vlr/msc_vlr_tests.c
@@ -486,11 +486,6 @@
 		.description = "Layer3 Call Control (CC)",
 		.enabled = 1, .loglevel = LOGL_DEBUG,
 	},
-	[DMM] = {
-		.name = "DMM",
-		.description = "Layer3 Mobility Management (MM)",
-		.enabled = 1, .loglevel = LOGL_DEBUG,
-	},
 	[DVLR] = {
 		.name = "DVLR",
 		.description = "Visitor Location Register",