arm64: dts: qcom: qcs6490-rb3gen2: Add sound card

arm64: dts: qcom: qcs6490-rb3gen2: Add sound card

Add the sound card node with tested playback over WSA8835 speakers
and digital on-board mics.

Co-developed-by: Prasad Kumpatla <quic_pkumpatl@quicinc.com>
Signed-off-by: Prasad Kumpatla <quic_pkumpatl@quicinc.com>
Signed-off-by: Mohammad Rafi Shaik <mohammad.rafi.shaik@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250903151337.1037246-7-mohammad.rafi.shaik@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>