arm64: dts: qcom: sdm845-db845c: add wifi variant property

Dragonboard845c doesn't have board-specific board-id programmed, it uses
generic 0xff. Thus add the property with the 'variant' of the
calibration data.

Note: the driver will check for the calibration data for the following
IDs, so older board-2.bin files that were distributed as a part of
Linaro releases will continue to work.

- 'bus=snoc,qmi-board-id=ff,qmi-chip-id=30214,variant=Thundercomm_DB845C'
- 'bus=snoc,qmi-board-id=ff,qmi-chip-id=30214'
- 'bus=snoc,qmi-board-id=ff'

For the reference, the board is identified by the driver in the
following way:

ath10k_snoc 18800000.wifi: qmi chip_id 0x30214 chip_family 0x4001 board_id 0xff soc_id 0x40030001
ath10k_snoc 18800000.wifi: qmi fw_version 0x2009856b fw_build_timestamp 2018-07-19 12:28 fw_build_id QC_IMAGE_VERSION_STRING=WLAN.HL.2.0-01387-QCAHLSWMTPLZ-1

Fixes: 3f72e2d3 ("arm64: dts: qcom: Add Dragonboard 845c")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220403105711.1173161-1-dmitry.baryshkov@linaro.org

arch/arm64/boot/dts/qcom/sdm845-db845c.dts

@@ -1051,6 +1051,7 @@ &wifi {
 	vdd-3.3-ch0-supply = <&vreg_l25a_3p3>;
 
 	qcom,snoc-host-cap-8bit-quirk;
+	qcom,ath10k-calibration-variant = "Thundercomm_DB845C";
 };
 
 /* PINCTRL - additions to nodes defined in sdm845.dtsi */