staging: wilc1000: fix infoleak in wilc_wfi_cfgoperations

"mac" is an array allocated in stack without being initialized,
and will be sent out via "nla_put". The dump_station() is supposed
to initialize the mac address; otherwise, sensitive data in kernel
stack will be leaked. To fix this, copy the mac address to it.

Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>