gprs: Fix warnings on funny casts for the return statement

Change gprs_nsvc_reset to return void instead of a int
as the gb_proxy.c currently ignores the reutnr value anyway.

Change the caller inside gprs_ns to return the newly allocated
nsvc instead of the return of gprs_nsvc_reset.
diff --git a/openbsc/src/gprs/gprs_ns.c b/openbsc/src/gprs/gprs_ns.c
index 04d17b8..467e43a 100644
--- a/openbsc/src/gprs/gprs_ns.c
+++ b/openbsc/src/gprs/gprs_ns.c
@@ -924,7 +924,7 @@
 }
 
 /* Initiate a RESET procedure */
-int gprs_nsvc_reset(struct gprs_nsvc *nsvc, uint8_t cause)
+void gprs_nsvc_reset(struct gprs_nsvc *nsvc, uint8_t cause)
 {
 	/* Mark NS-VC locally as blocked and dead */
 	nsvc->state = NSE_S_BLOCKED;
@@ -935,8 +935,6 @@
 	}
 	/* Start Tns-reset */
 	nsvc_start_timer(nsvc, NSVC_TIMER_TNS_RESET);
-
-	return nsvc;
 }
 
 /* Establish a connection (from the BSS) to the SGSN */
@@ -954,5 +952,6 @@
 	nsvc->nsvci = nsvci;
 	nsvc->remote_end_is_sgsn = 1;
 
-	return gprs_nsvc_reset(nsvc, NS_CAUSE_OM_INTERVENTION);
+	gprs_nsvc_reset(nsvc, NS_CAUSE_OM_INTERVENTION);
+	return nsvc;
 }