iwlwifi: api: remove ttl field from TX command

This doesn't really exist in the firmware, it's just some
leftover from older versions. Remove it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220210181930.b8190c27dc87.Ie5b5f8c68ecafd1b51d197fc1273b024bc1575a4@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>