nl80211: validate number of probe response CSA counters

Due to an apparent copy/paste bug, the number of counters for the
beacon configuration were checked twice, instead of checking the
number of probe response counters. Fix this to check the number of
probe response counters before parsing those.

Cc: stable@vger.kernel.org
Fixes: 9a774c78

 ("cfg80211: Support multiple CSA counters")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>