The next migration step is to use the common code in generic driver
for Realtek driver.  This is no drastic change and there should be no
real functional changes, as the generic parser code comes from Realtek
driver originally.

As Realtek driver requires the generic parser code, it needs a
reverse-selection of CONFIG_SND_HDA_GENERIC kconfig.
Signed-off-by: Takashi Iwai <tiwai@suse.de>