wifi: iwlwifi: remove 'use_tfh' config to fix crash

wifi: iwlwifi: remove 'use_tfh' config to fix crash

This is equivalent to 'gen2', and it was always confusing to have
two identical config entries. The split config patch actually had
been originally developed after removing 'use_tfh" and didn't add
the use_tfh in the new configs as they'd later been copied to the
new files. Thus the easiest way to fix the init crash here now is
to just remove use_tfh (which is erroneously unset in most of the
configs now) and use 'gen2' in the code instead.

There's possibly still an unwind error in iwl_txq_gen2_init() as
it crashes if TXQ 0 fails to initialize, but we can deal with it
later since the original failure is due to the use_tfh confusion.

Tested-by: Xi Ruoyao <xry111@xry111.site>
Reported-and-tested-by: Niklāvs Koļesņikovs <pinkflames.linux@gmail.com>
Reported-and-tested-by: Jeff Chua <jeff.chua.linux@gmail.com>
Reported-and-tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217622
Link: https://lore.kernel.org/all/9274d9bd3d080a457649ff5addcc1726f08ef5b2.camel@xry111.site/
Link: https://lore.kernel.org/all/CAAJw_Zug6VCS5ZqTWaFSr9sd85k%3DtyPm9DEE%2BmV%3DAKoECZM%2BsQ@mail.gmail.com/
Fixes: 19898ce9cf8a ("wifi: iwlwifi: split 22000.c into multiple files")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20230710145038.84186-2-johannes@sipsolutions.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>