wfx: update to firmware 3.16.1

The firmware 3.16.1 has been released the 2023-05-02.

Here the last modifications (only modifications tagged [LMAC] have an
impact on Linux):

  * [1670] - [LMAC] Fixed support for WDS 4 address frames
  * [1813] - [LMAC] Fixed an error that was causing the scan complete
                    indication to be blocked
  * [1832] - [UMAC] Fixed an issue blocking connection to specific Asus
                    routers
  * [1820] - [UMAC] Added a new API to obtain Wi-Fi diagnostics
                    information
  * [1825] - [UMAC] The TX rate mask can be applied in AP mode
  * [1822] - [UMAC] Fixed an error that was causing access point packets
                    to be encrypted multiple times

  * [1800] - [UMAC] Add an API to forward probe request when running in
                    AP mode

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>