drm/vc4: hdmi: Add a name to the codec DAI component

Since the components for a given device in ASoC are identified by their
name, it makes sense to add one even though it's not strictly necessary.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708144555.718404-1-maxime@cerno.tech