gprs_gmm.c: Send XID reset with received TLLI

Otherwise lower layers will end up using a TLLI from PTMSI which was not
yet announced to the MS if it is still not in GMM attached state, as
showcased by SGSN_Tests.TC_attach_req_id_req_ra_update.

Related: OS#3957, OS#4245
Change-Id: Ide51726abb82f5784eca4ab8d62b2ad8512be843
diff --git a/src/sgsn/gprs_gmm.c b/src/sgsn/gprs_gmm.c
index 7a09760..f62d0d1 100644
--- a/src/sgsn/gprs_gmm.c
+++ b/src/sgsn/gprs_gmm.c
@@ -1626,7 +1626,7 @@
 			/* send a XID reset to re-set all LLC sequence numbers
 			 * in the MS */
 			LOGGBP(llme, DMM, LOGL_NOTICE, "LLC XID RESET\n");
-			gprs_llgmm_reset(llme);
+			gprs_llgmm_reset_oldmsg(msg, GPRS_SAPI_GMM, llme);
 		}
 		/* The MS has to perform GPRS attach */
 		/* Device is still IMSI attached for CS but initiate GPRS ATTACH,