[Sound-open-firmware] Disable SOF power management on BYT by default?

Hi,

It seems the power management is enabled by default for platforms, since I found SET_RUNTIME_PM_OPS is set in both sof-acpi-dev.c and sof-pci-dev.c.

However, I feel only APL+ platforms can support this feature. So maybe we need to disable this on BYT by default?

Thanks Mengdong