Comment # 12 on bug 1095265 from Takashi Iwai

Good to hear!  So was the original problem (the missing output after boot) also
fixed by that, too?

The patch you mentioned should fix the missing firmware in initrd, as it adds
the firmware file listed in module information exposed to user-space so that
dracut can fetch it automatically.

The patch was already queued to my SLE15-UPDATE branch (as well as other two
i915 fixes), and it'll be included in the next update kernel.

Until you get that, just keep using the manually tweaked initrd.