wifi: mac80211: fix key tailroom accounting leak

wifi: mac80211: fix key tailroom accounting leak

For keys added by ieee80211_gtk_rekey_add(), we assume that
they're already present in the hardware and set the flag
KEY_FLAG_UPLOADED_TO_HARDWARE. However, setting this flag
needs to be paired with decrementing the tailroom needed,
which was missed.

Fixes: f52a0b408ed1 ("wifi: mac80211: mark keys as uploaded when added by the driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20251019115358.c88eafb4083e.I69e9d4d78a756a133668c55b5570cf15a4b0e6a4@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>