ALSA: hda - Drop hard dependency on CONFIG_SND_DYNAMIC_MINORS

Currently HDMI codec driver sets the hard dependency (reverse
selection) on CONFIG_SND_DYNAMIC_MINORS because the recent codecs may
support more than two PCMs.  But, this doesn't mean that we need
always this option, since there can be a single PCM stream even with
the modern codecs.

This patch drops the hard dependency again but give more sensible
error message when no enough PCMs are available due to the lack of
this option.

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