ALSA: hda/hdmi - consider eld_valid also in sync_eld_via_acomp()

In the commit 7f641e26

 (ALSA: hda/hdmi
- Consider eld_valid when reporting jack event) the eld_valid check was
added for the jack event reports. Do the same in sync_eld_via_acomp()
function. Apparently, it is required for the NVIDIA proprietary driver
(monitor presence reported first, but ELD is available later).

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>