linux: Add kernel config required for QCA6390 bluetooth (XPS 9310)

This commit aims to upstream some kernel config patches from the [xps
9310 module in the nixos-hardware repo][1]. These patches have been in
use by at least a few community members for around 10 months and seem to
consistently and successfully enable bluetooth support for XPS 9310
models that come with the QCA6390 connectivity chip.

Without these patches, bluetooth will not work on the Dell XPS 9310
laptop models that come with the QCA6390. *Note that this isn't all XPS
9310 devices, but seems to be all devices shipped with 32GB RAM.*

The motivation for upstreaming is pretty simple: currently we have to
build the entire kernel every time we want to update it, which takes a
good half hour at least on this little laptop :)

The `whenAtLeast` version params were determined via the entries for
each parameter found at https://cateee.net/lkddb (linked for each
below).

Added config parameters:

- `BT_QCA` - provides the `btqca` module.
  https://cateee.net/lkddb/web-lkddb/BT_QCA.html
- `BT_HCIUART_QCA` - required for QCA6390 bluetooth support.
  Requires `BT_HCIUART`, `BT_HCIUART_SERDEV`
  https://cateee.net/lkddb/web-lkddb/BT_HCIUART_QCA.html
- `BT_HCIUART_SERDEV`
  Requires `SERIAL_DEV_BUS`, `BT_HCIUART`
  https://cateee.net/lkddb/web-lkddb/BT_HCIUART_SERDEV.html
- `BT_HCIUART`
  Requires `SERIAL_DEV_BUS`, `TTY`
  https://cateee.net/lkddb/web-lkddb/BT_HCIUART.html
- `SERIAL_DEV_CTRL_TTYPORT`
  Requires `TTY`, `SERIAL_DEV_BUS` != module
  https://cateee.net/lkddb/web-lkddb/SERIAL_DEV_CTRL_TTYPORT.html
- `SERIAL_DEV_BUS`
  https://cateee.net/lkddb/web-lkddb/SERIAL_DEV_BUS.html

Fwiw, these parameters are also set in [the default Arch config][2].

[1]: https://github.com/NixOS/nixos-hardware/blob/master/dell/xps/13-9310/default.nix
[2]: https://github.com/archlinux/svntogit-packages/blob/packages/linux/trunk/config

pkgs/os-specific/linux/kernel/common-config.nix

@@ -747,10 +747,17 @@ let
 
       BSD_PROCESS_ACCT_V3 = yes;
 
+      SERIAL_DEV_BUS = whenAtLeast "4.11" yes; # enables support for serial devices
+      SERIAL_DEV_CTRL_TTYPORT = whenAtLeast "4.11" yes; # enables support for TTY serial devices
+
+      BT_HCIUART_QCA = whenAtLeast "4.3" yes; # Qualcomm Atheros protocol support
+      BT_HCIUART_SERDEV = whenAtLeast "4.12" yes; # required by BT_HCIUART_QCA
+      BT_HCIUART = whenAtLeast "2.5.45" module; # required for BT devices with serial port interface (QCA6390)
       BT_HCIUART_BCSP = option yes;
       BT_HCIUART_H4   = option yes; # UART (H4) protocol support
       BT_HCIUART_LL   = option yes;
       BT_RFCOMM_TTY   = option yes; # RFCOMM TTY support
+      BT_QCA = whenAtLeast "4.3" module; # enables QCA6390 bluetooth
 
       CLEANCACHE = option yes;
       CRASH_DUMP = option no;