staging: wfx: update with the firmware API 3.8

The firmware API 3.8 introduces new statistic counters. These changes
are backward compatible.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20210913130203.1903622-14-Jerome.Pouiller@silabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>