arm64: dts: qcom: sdm845*: replace i2s reg with constant

Make it easier to understand what the reg in those nodes is by using the
constants provided by qcom,q6dsp-lpass-ports.h.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220603094710.64591-1-luca.weiss@fairphone.com