mac80211: read calibration variant from device tree

mac80211: read calibration variant from device tree

ath10k and ath11k support reading calibration variants from the device
tree to locate the correct Board Description File (BDF). The ath12k-wsi
binding already describes using qcom,calibration-variant but it is not
implemented in the driver.

Many ath12k designs expose all the radios under a single phy, each of
which typically require a separate BDF. Without this, the radios may not
come up or will not be calibrated correctly.

Fix this by parsing the device tree for the generation-agnostic
qcom,calibration-variant. This allows the driver to properly select,
read and apply the correct BDF.

Additionally, the ath12k-wsi binding documentation describes using the
generation-specific qcom,ath12k-calibration-variant binding as well as
the generation-agnostic qcom,calibration-variant binding to load
board-specific calibration data from the device tree. However, the
driver never implemented either of these.

Given that no devices currently supported use
qcom,ath12k-calibration-variant and the previous patch implements
qcom,calibration-variant, drop the generation-specific version from the
binding to prevent future confusion.

Tested on Askey SBE1V1K.

Signed-off-by: Andrew LaMarche <andrewjlamarche@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/21767
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>