Nimble: Fixes for memory leak / optimization

components/bt/host/nimble/Kconfig.in

@@ -480,7 +480,7 @@ config BT_NIMBLE_HS_STOP_TIMEOUT_MS
 config BT_NIMBLE_HOST_BASED_PRIVACY
     bool "Enable host based privacy for random address."
     default n
-    depends on BT_NIMBLE_ENABLED && !IDF_TARGET_ESP32
+    depends on BT_NIMBLE_ENABLED && IDF_TARGET_ESP32
     help
         Use this option to do host based Random Private Address resolution.
         If this option is disabled then controller based privacy is used.

components/bt/host/nimble/esp-hci/src/esp_nimble_hci.c

@@ -366,6 +366,7 @@ static int host_rcv_pkt(uint8_t *data, uint16_t len)
             assert(evbuf != NULL);
         }
 
+        memset(evbuf, 0, sizeof *evbuf);
         memcpy(evbuf, &data[1], totlen);
 
         rc = ble_hci_trans_ll_evt_tx(evbuf);