ASoC: hdmi-codec: dump ELD through procfs

Use freshly added API and add eld#n files to procfs for the ASoC cards
utilizing HDMI codec. This simplifies debugging of the possible ASoC /
HDMI / DisplayPort audio issues.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250124-alsa-hdmi-codec-eld-v1-2-bad045cfaeac@linaro.org