sunxi-sound: Move registration of hdmi-audio devices to sunxi-hdmi code

Registering the hdmi audio-devices when not using hdmi means that userspace
may end up trying to use hdmi while it is not working. When hdmi-audio is
not enabled, and userspace still tries to use it the audio-using app(s) will
hang when trying to write to the audio-device, since the write will never
complete when the video-part is not consuming any hdmi-audio.

Note that this patch does not unregister the audio-card again if the hdmi
block is powered down (dpms / blank screen), so as to avoid audio-streaming
apps to crash / abort because the soundcard has gone away. Instead the app
will pause (write will block) on monitor powerdown and resume again when
the monitor powers back on.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi-sound: Cleanup spdif_used parsing

Various spdif_used parsing fixes / cleanups:
1) sun4i_spdma was not honoring spdif_used
2) There are 4 .ko files build for spdif, having each of them complain when
   spdif_used is not set is a bit too much
3) script_parser_fetch's last argument is an integer count, not a byte count
4) Fix cleaning up of platform_device when driver registration fails
5) On module onload properly remove both the device and the driver

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi-sound: Honor audio_used fex file setting

So that devices which don't have analog audio hooked up don't get an
alsa sound-card for it.

While almost rewriting this code anyways also fix:
1) Cleaning up of platform_device when driver registration fails
2) On module onload properly remove both the device and the driver

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi-sound: Honor capture_used and playback_used

So that the onboard-coded alsa-card does not advertises that it can playback /
capture sound on boards which cannot.

Note playback_used is a linux-sunxi.org fex file extension for boards which use
the onboard audio codec only for input, such as the uhost_u1a & mk802-a10s.

Since playback_used is a linux-sunxi.org fex file extension, it is assumed to
be 1 when not set.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi-pm: Silence debug spew

Esp. the annoying [pm]valid messages which otherwise keep getting spewed
from time to time.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>