arm64: dts: qcom: sdm845-oneplus: add ath10k calibration variant

arm64: dts: qcom: sdm845-oneplus: add ath10k calibration variant

SDM845-based Oneplus 6 and 6T have their own calibration files
for the WCN3990 WiFi/Bluetooth radio with the ath10k driver.
Add the calibration variant name to the DTS to reflect this to
allow using the calibration files from linux-firmware.

[David] Adjust the compatible as ath10k-calibration-variant is deprecated

Signed-off-by: Dylan Van Assche <me@dylanvanassche.be>
Signed-off-by: David Heidelberg <david@ixit.cz>
Link: https://lore.kernel.org/r/20251110-sdm845-calibration-variants-v1-1-2c536ada77c2@ixit.cz
Signed-off-by: Bjorn Andersson <andersson@kernel.org>