staging: wfx: rework wfx_configure_filter()

wfx_configure_filter() lacks of coherency. In add, some corner cases
seems to not been handled properly. Rework the whole function().

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200415161147.69738-4-Jerome.Pouiller@silabs.com


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