CC      drivers/tty/serial/8250/8250_port.o
  AR      drivers/dma/built-in.a
  CC [M]  sound/soc/apple/mca.o
  CC      drivers/tty/serial/8250/8250_dwlib.o
sound/soc/apple/mca.c: In function 'mca_set_runtime_hwparams':
sound/soc/apple/mca.c:528:37: warning: unused variable 'rtd' [-Wunused-variable]
  528 |         struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
      |                                     ^~~
  CC      drivers/tty/serial/8250/8250_pci.o
  LD [M]  sound/soc/apple/snd-soc-apple-mca.o
  CC      drivers/tty/serial/8250/8250_exar.o
  CC      drivers/tty/serial/8250/8250_fsl.o
  LD [M]  sound/soc/snd-soc-core.o