arm64: dts: db820c: Add qcom,apq8096 to compatible string

Add qcom,apq8096 to compatible string.
This compatible is defined in Documentation/devicetree/bindings/arm/qcom.txt
and is needed for e.g. drivers/cpufreq/qcom-cpufreq-kryo.c to be probed
correctly (and for drivers/cpufreq/cpufreq-dt-platdev.c to work properly).

Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>