arm64: dts: qcom: sm6375-pdx225: Fix remoteproc firmware paths

They were previously missing the SoC name. Fix it.

Fixes: a2ad207c ("arm64: dts: qcom: sm6375-pdx225: Enable ADSP & CDSP")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230517-topic-murray-fwname-v1-1-923e87312249@linaro.org