staging: wfx: ensure that packet_id is unique

In current code, packet_id is derivated from mac802.11 packet sequence
number, but this number is only unique for a station. It is not
sufficient.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200115135338.14374-60-Jerome.Pouiller@silabs.com


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