staging: brcm80211: bugfix for softmac crash on multi cpu configurations

Solved a locking issue that resulted in driver crashes with the 43224 and 43225
chips. The problem has been reported on several fora. Root cause was two fold:
hardware was being manipulated by two unsynchronized threads, and a scan
operation could interfere with an ongoing dynamic calibration process. Fix was
to invoke a lock on wl_ops_config() operation and to set internal flags when a
scan operation is started and stopped.

Please add this to the staging-linus branch.

Reviewed-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>