staging: wfx: simplify memory allocation in wfx_update_filtering()

staging: wfx: simplify memory allocation in wfx_update_filtering()

Original code did not handle case where kmalloc failed. By the way, it
is more convenient to allocate and build HIF message in
hif_set_beacon_filter_table() instead of to ask to caller function to
build it.

Fixes: 40115bbc40e2 ("staging: wfx: implement the rest of mac80211 API")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20191008094232.10014-2-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>