ALSA: hda/realtek - Fix the possible conflicts of Bass Speaker name

When the multi-io is added to the two speaker output configuration,
the parser would try to add yet another "Bass Speaker" control since
it checks only cfg->line_outs.  Add a workaround for it by simply
passing the channel name in the case of multi-io outputs.

Signed-off-by: Takashi Iwai <tiwai@suse.de>