ALSA: HDA: Realtek ALC88x: Do not over-initialize speakers and hp that are primary outputs

Do not initialize again the what has already been initialized as
multi outs, as this breaks surround speakers.

Tested-by: Bartłomiej Żogała <nusch88@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>