arm64: dts: qcom: sdm845-akatsuki: Round down l22a regulator voltage

2700000 is not a multiple of pmic4_pldo's step size of 8000 (with base
voltage 1664000), resulting in pm8998-rpmh-regulators not probing.  Just
as we did with MSM8998's Sony Yoshino Poplar [1], round the voltages
down to err on the cautious side and leave a comment in place to
document this discrepancy wrt downstream sources.

[1]: https://lore.kernel.org/linux-arm-msm/20220507153627.1478268-1-marijn.suijten@somainline.org/

Fixes: 30a7f99b ("arm64: dts: qcom: Add support for SONY Xperia XZ2 / XZ2C / XZ3 (Tama platform)")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220620211212.269956-1-marijn.suijten@somainline.org

arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts

@@ -19,8 +19,9 @@ &vreg_l14a_1p8 {
 };
 
 &vreg_l22a_2p8 {
-	regulator-min-microvolt = <2700000>;
-	regulator-max-microvolt = <2700000>;
+	/* Note: Round-down from 2700000 to be a multiple of PLDO step-size 8000 */
+	regulator-min-microvolt = <2696000>;
+	regulator-max-microvolt = <2696000>;
 };
 
 &vreg_l28a_2p8 {