drm/vc4: hdmi: Stop checking for enabled output in audio

drm/vc4: hdmi: Stop checking for enabled output in audio

The current HDMI driver, in vc4_hdmi_audio_can_stream() checks whether
the display output is enabled.

This has been there in one form or the other since the introduction of
the audio support in the VC4 HDMI driver in commit b5780ae2a73c
("drm/vc4: Add HDMI audio support"), but no justification for this check
is in the commit message, or in the discussions around the patches.

One can only assume this was done to prevent a user from playing audio
on the ALSA soundcard when the monitor doesn't support it.

However, this is causing some issues. Indeed, Kodi, for example, was
hitting some errors if it was streaming audio during a modeset. With the
theory above, it does make sense, but the display and audio threads are
typically completely different processes with no opportunity to
synchronise which makes it hard to workaround.

Removing that check also doesn't seem to cause any trouble, so let's
just remove it.

Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Link: https://lore.kernel.org/r/20220613144800.326124-25-maxime@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>