While upgrading the Linux kernel on my XPS13, I noticed that I could no longer find the option to enable the ASoC driver that is needed when the sound card is running in I2S mode. The symbol (SND_SOC_INTEL_BROADWELL_MACH) was still there, but it didn't show up at the expected location. I also had all dependencies enabled, so I was a bit surprised it didn't show up. After looking again, I noticed this in the dependencies:
DW_DMAC_CORE [=m]=y