if_iwm - The iwm_prepare_card_hw() in iwm_attach() is only needed on 8K hw.
- Doing the iwm_prepare_card_hw() call in iwm_attach() only on Family 8000
hardware matches the code in Linux iwlwifi.
- While there remove DEFAULT_MAX_TX_POWER definition which is unused, and
has a value different from IWL_DEFAULT_MAX_TX_POWER in iwlwifi.
Submitted by: Augustin Cavalier <waddlesplash@gmail.com> (Haiku)
Obtained from: DragonFlyBSD (e8560f8dc58df12a7c79a6bb4e6ccb156e001085)