staging: wfx: avoid duplicate updating of beacon template

staging: wfx: avoid duplicate updating of beacon template

When ERP changes, mac80211 call wfx_bss_info_changed() with
BSS_CHANGED_ERP_* and with BSS_CHANGED_BEACON.

The driver already update beacon template because of
BSS_CHANGED_BEACON. It is not necessary to also update beacon template
because of BSS_CHANGED_ERP_*.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200410133239.438347-14-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>