arm64: dts: qcom: sm8250: correct compatible for sm8250-mtp

Qualcomm boards should define two compatible strings: one for board,
anoter one for SoC family. sm8250-mtp.dts lists just the board
compatible, which makes it incompatible with qcom.yaml schema.
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Fixes: 60378f1a ("arm64: dts: qcom: sm8250: Add sm8250 dts file")
Link: https://lore.kernel.org/r/20200930112133.2091505-1-dmitry.baryshkov@linaro.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

arch/arm64/boot/dts/qcom/sm8250-mtp.dts

@@ -14,7 +14,7 @@
 
 / {
 	model = "Qualcomm Technologies, Inc. SM8250 MTP";
-	compatible = "qcom,sm8250-mtp";
+	compatible = "qcom,sm8250-mtp", "qcom,sm8250";
 
 	aliases {
 		serial0 = &uart12;