bluez: remove sap feature from build

Remove the SAP plugin/feature from bluez as it pollutes bluetooth logs with errors :

```
bluetoothd[16277]: profiles/sap/server.c:sap_server_register() Sap driver initialization failed.
bluetoothd[16277]: sap-server: Operation not permitted (1)
```

SAP= SIM Access Profile, this feature has been removed from mainline and only a dummy implementation remains : https://git.kernel.org/pub/scm/bluetooth/bluez.git/commit/profiles/sap?id=3a140aa35b7b7dc1d7b031eec40590187f70a980

More context
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=803265#45

pkgs/os-specific/linux/bluez/default.nix

@@ -85,7 +85,6 @@ in stdenv.mkDerivation rec {
     "--enable-mesh"
     "--enable-midi"
     "--enable-nfc"
-    "--enable-sap"
     "--enable-sixaxis"
     "--enable-btpclient"
     "--enable-hid2hci"