ARM: dts: qcom: apq8084: fix compatible for l2-cache

The compatible "qcom,arch-cache" for l2-cache does not exist, and all
other Qualcomm boards use just "cache" for it. Fix it.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221013190657.48499-2-luca@z3ntu.xyz