arm64: dts: qcom: qcs6490: Introduce Radxa Dragon Q6A

arm64: dts: qcom: qcs6490: Introduce Radxa Dragon Q6A

Radxa Dragon Q6A is a single board computer, based on the Qualcomm
QCS6490 platform.

Features enabled and working:

- Configurable I2C/SPI/UART from 40-Pin GPIO
- Three USB-A 2.0 ports
- RTL8111K Ethernet connected to PCIe0
- eMMC module
- SD card
- M.2 M-Key 2230 PCIe 3.0 x2
- Headphone jack
- Onboard thermal sensors
- QSPI controller for updating boot firmware
- ADSP remoteproc (Type-C and charging features disabled in firmware)
- CDSP remoteproc (for AI applications using QNN)
- Venus video encode and decode accelerator

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Xilin Wu <sophon@radxa.com>
Link: https://lore.kernel.org/r/20250929-radxa-dragon-q6a-v5-2-aa96ffc352f8@radxa.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>