staging: brcm80211: fix perimeter locking in wl_ops_bss_info_changed

Several code path in the wl_ops_bss_info_changed() callback were not
using the perimeter lock. This gives potential of raise conditions
so lock/unlock calls have been added.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Reviewed-by: Roland Vossen <rvossen@broadcoom.com>
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>