ASoc: hdmi_codec: fix startup error when multicodecs are used

ASoc: hdmi_codec: fix startup error when multicodecs are used

due to playback and capture will call startup at the same time
when voip call, but hdmi_codec driver only support playback

[   51.134149] hdmi-audio-codec hdmi-audio-codec.6.auto: hdmi_codec_startup()
[   51.134179] hdmi-audio-codec hdmi-audio-codec.6.auto: Only one simultaneous stream supported!
[   51.134197] hdmi-audio-codec hdmi-audio-codec.6.auto: ASoC: can't open codec i2s-hifi: -22
[   51.143250] hdmi-audio-codec hdmi-audio-codec.6.auto: hdmi_codec_startup()
[   51.143277] hdmi-audio-codec hdmi-audio-codec.6.auto: Only one simultaneous stream supported!
[   51.143294] hdmi-audio-codec hdmi-audio-codec.6.auto: ASoC: can't open codec i2s-hifi: -22
[   51.157546] hdmi-audio-codec hdmi-audio-codec.6.auto: hdmi_codec_startup()
[   51.157584] hdmi-audio-codec hdmi-audio-codec.6.auto: Only one simultaneous stream supported!
[   51.157603] hdmi-audio-codec hdmi-audio-codec.6.auto: ASoC: can't open codec i2s-hifi: -22

Change-Id: I970695dbe19f070579aacd044e6a01c44e687a2e
Signed-off-by: zhangjun <zhangjun@rock-chips.com>