rest_octets: Suffix encoder functiosn with _encode

... otherwise it's not really clear what they do.

Change-Id: I08e0ca9a8d13c7aa40b9d90f34f0e13adb87d4e0
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 319969a..56fed0f 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -301,14 +301,14 @@
 gsm48_push_l3hdr;
 gsm48_att_tlvdef;
 gsm48_cc_msg_name;
-osmo_gsm48_rest_octets_si1;
-osmo_gsm48_rest_octets_si2quater;
-osmo_gsm48_rest_octets_si2ter;
-osmo_gsm48_rest_octets_si2bis;
-osmo_gsm48_rest_octets_si6;
-osmo_gsm48_rest_octets_si3;
-osmo_gsm48_rest_octets_si4;
-osmo_gsm48_rest_octets_si13;
+osmo_gsm48_rest_octets_si1_encode;
+osmo_gsm48_rest_octets_si2quater_encode;
+osmo_gsm48_rest_octets_si2ter_encode;
+osmo_gsm48_rest_octets_si2bis_encode;
+osmo_gsm48_rest_octets_si6_encode;
+osmo_gsm48_rest_octets_si3_encode;
+osmo_gsm48_rest_octets_si4_encode;
+osmo_gsm48_rest_octets_si13_encode;
 gsm48_rr_msg_name;
 gsm48_cc_state_name;
 gsm48_construct_ra;