Sync more NFAPI changes from multi-ue-proxy.git

Most notably, nfapi_rx_indication_pdu_t.data type is changed from
`uint8_t*` to `uint8_t[]`.  Also, renamed from `data` to
`rx_ind_data` to make it easier to find.

openair2/PHY_INTERFACE/phy_stub_UE.c

@@ -112,8 +112,8 @@ void fill_rx_indication_UE_MAC(module_id_t Mod_id,
   pdu->rx_indication_rel9.timing_advance_r9 = 0;
 
   // ulsch_buffer is necessary to keep its value.
-  pdu->data = malloc(buflen);
-  memcpy(pdu->data, ulsch_buffer, buflen);
+  assert(buflen <= NFAPI_RX_IND_DATA_MAX);
+  memcpy(pdu->rx_ind_data, ulsch_buffer, buflen);
   LOG_I(MAC, "buflen of rx_ind pdu_data = %u SFN.SF: %d.%d\n", buflen,
         frame, subframe);
   // estimate timing advance for MAC