Comment # 16 on bug 907692 from Takashi Iwai

They are just built-in, so they are always there on that kernel flavor.  Hence
modprobe "fails".  But the functionality is already present on your system.

dracut is trying to load all listed modules without checking whether they are
already there, and it results in such error messages sometimes.  We've had a
similar report about pciehp driver, which is built-in on kernel-desktop flavor.