Pass paging group instead of imsi where later is not needed

Change-Id: Id0663a81f439f2d0b893b0d34f85a6db1927ef8e
diff --git a/src/gprs_rlcmac.cpp b/src/gprs_rlcmac.cpp
index e381b11..cbfc87f 100644
--- a/src/gprs_rlcmac.cpp
+++ b/src/gprs_rlcmac.cpp
@@ -29,13 +29,13 @@
 extern void *tall_pcu_ctx;
 
 int gprs_rlcmac_paging_request(uint8_t *ptmsi, uint16_t ptmsi_len,
-	const char *imsi)
+			       uint16_t pgroup)
 {
 	LOGP(DRLCMAC, LOGL_NOTICE, "TX: [PCU -> BTS] Paging Request (CCCH)\n");
 	bitvec *paging_request = bitvec_alloc(22, tall_pcu_ctx);
 	bitvec_unhex(paging_request, DUMMY_VEC);
 	int plen = Encoding::write_paging_request(paging_request, ptmsi, ptmsi_len);
-	pcu_l1if_tx_pch(paging_request, plen, (char *)imsi);
+	pcu_l1if_tx_pch(paging_request, plen, pgroup);
 	bitvec_free(paging_request);
 
 	return 0;