arm64: dts: qcom: Add SM7225 device tree

The Snapdragon 750G (sm7225) is software-wise very similar to Snapdragon
690 (sm6350) with minor differences in clock speeds and as added here,
it uses the Kryo 570 instead of Kryo 560.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211007212444.328034-11-luca@z3ntu.xyz