dt-bindings: qcom,smd-rpm: update maintainers (drop Kathiravan)

Kathiravan's email bounces (585: Recipient address rejected:
undeliverable address: No such user here) so switch maintainers to Andy
and Bjorn (as Qualcomm platform maintainers).

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220401202759.191560-1-krzysztof.kozlowski@linaro.org