wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices

ath12k is a new mac80211 driver for Qualcomm Wi-Fi 7 devices, first
supporting QCN9274 and WCN7850 PCI devices. QCN9274 supports both AP
and station; WCN7850 supports only station mode. Monitor mode is not
(yet) supported. Only PCI bus devices are supported.

ath12k is forked from an earlier version of ath11k. It was simpler to
have a "clean start" for the new generation and not try to share the
code with ath11k. This makes maintenance easier and avoids major
changes in ath11k, which would have significantly increased the risk
of regressions in existing setups.

ath12k uses le32 and cpu_to_le32() macros to handle endian
conversions, instead of using the firmware byte swap feature utilized
by ath11k. There is only one kernel module, named ath12k.ko.

Currently ath12k only supports HE mode (IEEE 802.11ax) or older, but
work is ongoing to add EHT mode (IEEE 802.11be) support.

The size of the driver is ~41 kLOC and 45 files. To make the review
easier, this initial version of ath12k does not support Device Tree,
debugfs or any other extra features. Those will be added later, after
ath12k is accepted to upstream.

The driver is build tested by Intel's kernel test robot with both GCC
and Clang. Sparse reports no warnings. The driver is mostly free of
checkpatch warnings, albeit few of the warnings are omitted on
purpose, list of them here:

https://github.com/qca/qca-swiss-army-knife/blob/master/tools/scripts/ath12k/ath12k-check#L52

The driver has had multiple authors who are listed in alphabetical
order below.

Co-developed-by: Balamurugan Selvarajan <quic_bselvara@quicinc.com>
Signed-off-by: Balamurugan Selvarajan <quic_bselvara@quicinc.com>
Co-developed-by: Baochen Qiang <quic_bqiang@quicinc.com>
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Co-developed-by: Bhagavathi Perumal S <quic_bperumal@quicinc.com>
Signed-off-by: Bhagavathi Perumal S <quic_bperumal@quicinc.com>
Co-developed-by: Carl Huang <quic_cjhuang@quicinc.com>
Signed-off-by: Carl Huang <quic_cjhuang@quicinc.com>
Co-developed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Co-developed-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Co-developed-by: P Praneesh <quic_ppranees@quicinc.com>
Signed-off-by: P Praneesh <quic_ppranees@quicinc.com>
Co-developed-by: Pradeep Kumar Chitrapu <quic_pradeepc@quicinc.com>
Signed-off-by: Pradeep Kumar Chitrapu <quic_pradeepc@quicinc.com>
Co-developed-by: Ramya Gnanasekar <quic_rgnanase@quicinc.com>
Signed-off-by: Ramya Gnanasekar <quic_rgnanase@quicinc.com>
Co-developed-by: Sriram R <quic_srirrama@quicinc.com>
Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Co-developed-by: Vasanthakumar Thiagarajan <quic_vthiagar@quicinc.com>
Signed-off-by: Vasanthakumar Thiagarajan <quic_vthiagar@quicinc.com>
Co-developed-by: Wen Gong <quic_wgong@quicinc.com>
Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>