staging: wilc1000: removes potential null dereference

This patch removes the error reported by smatch.
 - wilc_wfi_cfgoperations.c:674 scan() error:
   potential null dereference 'strHiddenNetwork.net_info'.  (kmalloc returns null)

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>