staging: wfx: remove "burst" mechanism

staging: wfx: remove "burst" mechanism

In the old days, the driver tried to reorder frames in order to send
frames from the same queue grouped to the firmware. However, the
firmware is able to do the job internally for a long time. There is no
reasons to keep this mechanism.

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200401110405.80282-5-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>