rename gsm0408_gprs_rcvmsg() to gsm0408_gprs_rcvmsg_gb()

This is the entry point for GMM from Gb.  We will create a new one
for Iu, so let's be explicit rather than implicit.

Change-Id: I93c074bf99db041117c0dc03dc8255879845a875
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index 889ac98..1e10701 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -2087,8 +2087,8 @@
 	return rc;
 }
 
-/* Main entry point for incoming 04.08 GPRS messages */
-int gsm0408_gprs_rcvmsg(struct msgb *msg, struct gprs_llc_llme *llme)
+/* Main entry point for incoming 04.08 GPRS messages from Gb */
+int gsm0408_gprs_rcvmsg_gb(struct msgb *msg, struct gprs_llc_llme *llme)
 {
 	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg);
 	uint8_t pdisc = gsm48_hdr_pdisc(gh);
diff --git a/openbsc/src/gprs/gprs_llc.c b/openbsc/src/gprs/gprs_llc.c
index 4d21963..71178c9 100644
--- a/openbsc/src/gprs/gprs_llc.c
+++ b/openbsc/src/gprs/gprs_llc.c
@@ -663,7 +663,7 @@
 		switch (llhp.sapi) {
 		case GPRS_SAPI_GMM:
 			/* send LL_UNITDATA_IND to GMM */
-			rc = gsm0408_gprs_rcvmsg(msg, lle->llme);
+			rc = gsm0408_gprs_rcvmsg_gb(msg, lle->llme);
 			break;
 		case GPRS_SAPI_SNDCP3:
 		case GPRS_SAPI_SNDCP5: