[PATCH] iwlwifi: Fix rate setting in probe request for HW sacn

This patch fixes setting of rates in probe request used in
HW scan. The bug was reported by Helmut Schaa <hschaa@suse.de>

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>