staging: wfx: split out wfx_filter_beacon()

staging: wfx: split out wfx_filter_beacon()

Currently, wfx_update_filtering() is sometime called only to apply the
value of wvif->filter_beacon to the hardware. It is nicer to have a
specific function for beacon filtering.

In add, an attentive reader would note that wfx_update_filtering() is
always called after change of wvif->filter_beacon. Thus, it not
necessary to store filter_beacon in the struct wfx_vif. We can just pass
it as parameter.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200415161147.69738-18-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>