wifi: iwlfiwi: mvm: Fix the rate reporting

The rate validation in mac80211 considers a rate to be valid iff both
the rate index and the count are positive. When the rate scaling is
managed in the driver and not enough traffic passed to set the actual
rate, the driver set the rate to be the optimal rate. However, the rate
count is not set and thus the rate is considered not valid. Fix it by
setting the count to 1.

Fixes: 3e99b4d2 ("wifi: mac80211: Sanity check tx bitrate if not provided by driver")
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250503224232.0d1d1e022d63.I76833c14ba1d66f9bea5c32b25a54d8b36f229ba@changeid