dt-bindings: mmc: sdhci-msm: Add compatible string for msm8226

Add msm8226 SoC specific compatible strings for qcom-sdhci controller.
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20210911232707.259615-3-luca@z3ntu.xyzSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/sdhci-msm.txt

@@ -13,6 +13,7 @@ Required properties:
 		string is added to support this change - "qcom,sdhci-msm-v5".
 	full compatible strings with SoC and version:
 		"qcom,apq8084-sdhci", "qcom,sdhci-msm-v4"
+		"qcom,msm8226-sdhci", "qcom,sdhci-msm-v4"
 		"qcom,msm8974-sdhci", "qcom,sdhci-msm-v4"
 		"qcom,msm8916-sdhci", "qcom,sdhci-msm-v4"
 		"qcom,msm8992-sdhci", "qcom,sdhci-msm-v4"