ALSA: hda - Drop unsol event handler for Intel HDMI codecs

We don't need to deal with the unsol events for Intel chips that are
tied with the graphics via audio component notifier.  Although the
presence of the audio component is checked at the beginning of
hdmi_unsol_event(), better to short cut by dropping unsol_event ops.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=204565


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