arm64: dts: qcom: qrb4210-rb2: add HDMI audio playback support

arm64: dts: qcom: qrb4210-rb2: add HDMI audio playback support

Add sound node and dsp-related piece to enable HDMI audio
playback support on Qualcomm QRB4210 RB2 board. That is the
only sound output supported for now.

The audio playback is verified using the following commands:

amixer -c0 cset iface=MIXER,name='SEC_MI2S_RX Audio Mixer MultiMedia1' 1
aplay -D hw:0,0 /usr/share/sounds/alsa/Front_Center.wav

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
Link: https://lore.kernel.org/r/20241112025306.712122-5-alexey.klimov@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>