wifi: iwlwifi: mld: don't remove all keys in mcast rekey

In the current code, if there was a rekey, we remove all the existing keys
from mac80211, then re-add the ones that the FW sent with
ieee80211_gtk_rekey_add, (newer FW will send also the existing GTKs/BIGTKs)
and then update the sequence number.

Instead of removing and re-adding the existing keys for no good reason,
we can just update the sequence of all keys, also of the ones that are
going to be replaced, and update again after the replace.

This change is required because ieee80211_gtk_rekey_add is going to be
changed to lookup the cipher from the old key instead of receiving it as an
argument, and for this it will need the old key(s), so we can't remove all
keys.

Note that with this change, in case that a key that existed before wowlan
is replaced, mac80211 will now call the driver to remove the old key and
add the new one (as opposed the previous behaviour, in which the key was
removed by the driver itself).
Of course we don't want to run the set_key callbacks in this case, so just
return early.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250710212632.f0b5e19f77f5.I958f4926f168cdad6d4d7720ebde2f5e812b297d@changeid