wifi: iwlwifi: simplify TX tracing

There's no need to calculate again whether data should
be included or be handled externally, just check if any
space for it was already reserved.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240512152312.a3d3b4796460.I85bd3029baee24ebf0be04db7d6bf01834090869@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>