wifi: iwlwifi: add iwlmld sub-driver

wifi: iwlwifi: add iwlmld sub-driver

iwlwifi is the driver of all Intel wifi devices since 2008.
Since then, the hardware has changed a lot, but the firmware
API has changed even more. The need to keep one driver that
supports all those different APIs led us to introduce a new
architecture circa 2012 which allowed us to keep the same
interface to the hardware (DMAs, Tx queues, etc...) with a
new layer to implement the mid-layer between mac80211 and
the firmware. The first component is called the 'transport'
and the latter is called 'operation_mode' a.k.a  op_mode.

In 2013 we took advantage of the new architecture to
introduce iwlmvm which allowed us to implement the, then,
new firmware API. This op_mode supports 7260 and up, those
devices supports support at least VHT.

Since then, wifi evolved and so did the firmware. It became
much bigger and took a lot of functionality from the driver.
It became increasingly hard to keep the same op_mode for the
newest devices and we experienced frequent regressions on
older devices. In order to avoid those regressions and keep
the code maintainable, we decided it was about time to start
a new op_mode.

iwlmld is a new op_mode that supports BE200 or newer if the
firmware being used is 97.ucode or newer. If the user has
an older devices or BE200 with .96.ucode, iwlmvm will be
loaded. Of course, this op_mode selection is seamless.

All the features supported in iwlmvm are supported in
iwlmld besides a few seldom used use cases: injection and
Hotspot 2.0. Those are under work.

A few points about the implementation:
 * iwlmld doesn't have any mutexes, it relies on the
   wiphy_lock
 * iwlmld is more "resource oriented": stations, links and
   interfaces are allocated and freed only after all the
   relevant flows are completed.
 * Firmware notifications' sizes are validated in a more
   structured way.

We would love to see this new op_mode merged in 6.15. The
firmware for this new driver (.97.ucode) is not yet publicly
available but it'll be sent very soon.
People eager to get an early version of this firmware can
contact Emmanuel at:
emmanuel.grumbach@intel.com

I've listed the people who directly contributed
code, but many others from various teams have
contributed in other ways.

Co-developed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Co-developed-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Co-developed-by: Daniel Gabay <daniel.gabay@intel.com>
Signed-off-by: Daniel Gabay <daniel.gabay@intel.com>
Co-developed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Co-developed-by: Anjaneyulu <pagadala.yesu.anjaneyulu@intel.com>
Signed-off-by: Anjaneyulu <pagadala.yesu.anjaneyulu@intel.com>
Co-developed-by: Yedidya Benshimol <yedidya.ben.shimol@intel.com>
Signed-off-by: Yedidya Benshimol <yedidya.ben.shimol@intel.com>
Co-developed-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Co-developed-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://lore.kernel.org/linux-wireless/20250216094321.537988-1-miriam.rachel.korenblit@intel.com/
[fix Kconfig, fix api/phy.h includes, SPDX tag and coding
 style issues, duplicated includes per 0-day robot]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>