gprs: more conditionals for Gb specific actions

Change-Id: I213d21b9ddbf19e56269defcc6aa65aca4947140
diff --git a/openbsc/src/gprs/gprs_sgsn.c b/openbsc/src/gprs/gprs_sgsn.c
index 722edec..8f9f453 100644
--- a/openbsc/src/gprs/gprs_sgsn.c
+++ b/openbsc/src/gprs/gprs_sgsn.c
@@ -315,8 +315,10 @@
 
 	LOGPDPCTXP(LOGL_INFO, pdp, "Forcing release of PDP context\n");
 
-	/* Force the deactivation of the SNDCP layer */
-	sndcp_sm_deactivate_ind(&pdp->mm->gb.llme->lle[pdp->sapi], pdp->nsapi);
+	if (pdp->mm->ran_type == MM_CTX_T_GERAN_Gb) {
+		/* Force the deactivation of the SNDCP layer */
+		sndcp_sm_deactivate_ind(&pdp->mm->gb.llme->lle[pdp->sapi], pdp->nsapi);
+	}
 
 	memset(&sig_data, 0, sizeof(sig_data));
 	sig_data.pdp = pdp;