staging:mei: wd_ops and wd_info should be static

wd_ops and wd_info structures are local to wd.c so mark them static

Cc: Oren Weil <oren.jer.weil@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>