cosmetic: use osmo_strlcpy() everywhere

Shorten some code and make obvious to the reader that the string copy is done
in a safe way.

Change-Id: I900726cf06d34128db22a3d3d911ee0d1423b1bd
diff --git a/openbsc/src/libmsc/smpp_openbsc.c b/openbsc/src/libmsc/smpp_openbsc.c
index 228e61d..657272e 100644
--- a/openbsc/src/libmsc/smpp_openbsc.c
+++ b/openbsc/src/libmsc/smpp_openbsc.c
@@ -133,12 +133,13 @@
 	sms->receiver = dest;
 	sms->dst.ton = submit->dest_addr_ton;
 	sms->dst.npi = submit->dest_addr_npi;
-	strncpy(sms->dst.addr, dest->extension, sizeof(sms->dst.addr)-1);
+	osmo_strlcpy(sms->dst.addr, dest->extension, sizeof(sms->dst.addr));
 
 	/* fill in the source address */
 	sms->src.ton = submit->source_addr_ton;
 	sms->src.npi = submit->source_addr_npi;
-	strncpy(sms->src.addr, (char *)submit->source_addr, sizeof(sms->src.addr)-1);
+	osmo_strlcpy(sms->src.addr, (char *)submit->source_addr,
+		     sizeof(sms->src.addr));
 
 	if (submit->esm_class & 0x40)
 		sms->ud_hdr_ind = 1;