drm/bridge: sii902x: Select SND_SOC_HDMI_CODEC if SND_SOC is configured

drm/bridge: sii902x: Select SND_SOC_HDMI_CODEC if SND_SOC is configured

To enable HDMI audio the SND_SOC_HDMI_CODEC needs to be
configured. Enable HDMI audio by selecting SND_SOC_HDMI_CODEC if
SND_SOC is configured. SND_SOC_HDMI_CODEC has no config menu entry and
should be selected automatically by the drivers using it.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
[narmstrong: atomatically -> automatically]
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191129152342.29145-1-jsarha@ti.com